Linux

Probably because PPAs only work on Ubuntu and there are more Linux distros and even then it meant having to build and test a package for a couple of different Ubuntu versions.

PPAs are flawed and limited to the Debian/Ubuntu ecosystem. They're a security issue as you really need to trust to the person or group who has set up the PPA (yet many people just added PPAs for all sorts of random software based on a Google search). They need to be maintained which is variable depending on the size of the project and for developers they're only a route to support part of the entire Linux ecosystem. They can also conflict with the main system provided packages and repost which can break entire systems or break upgrades (happened to me on Mint, and I needed to do a complete system reinstall to remove legacy package conflicts).

They've fallen out of fashion and rightly so.

There are other ways to get software to users. Arch has its AUR which is basically a huge open repo. OpenSuSE has its OBS which is also a huge open repo. These are also not without their risks as it's hard to curate everything on such an expansive repo. However others can take over packages if the original developer stops updating them, and you can see how the package was built rathe than just download binaries which allays some security concerns. They are also centralised and integrated into the system, while PPAs are a bit of a free for all.

Flatpaks are a popular alternative now - essentially you download and run software which runs in a sandbox with its own dependencies. Flatpaks share their sandboxed dependencies but it does lead to some bloat as you'll have system level libraries and separate Flatpak versions of the same libraries both installed and running at the same time. However it does mean software can be run on different systems without breaking the whole system if library dependencies don't match. There are issues around signing though - flathub allows anyone to maintain software rather than insisting on the original devs doing so. That allows software to be in a Flatpak that might otherwise not happen but adds a potential security risk of bad actors packaging software or not keeping up to date. They do now have a verified tick in Flathub to show if a Flatpak is official.

Snap is the Canonical alternative to Flatpak - it's controversial as it's proprietary and arguably more cumbersome. The backend is closed source and in canonical control. Snaps are also different and for more than just desktop apps and can be used to in servers and other software stacks, while Flatpak is focused only on desktop apps. Canonical arr also forcing Ubuntu users to use it - for example Firefox only comes in a snap on Ubuntu now. It has similar fundamental issues around bloat. It has mostly the same benefits and issues as Flatpak, although Flatpaks are faster to startup.

Appimage are another alternative way to distribute software - they are basically an all-in-one image. You are essentially "mounting" the image and running the software inside. It includes all the libraries etc within the image and uses those instead of the local libraries. It does and can use local libraries too; the idea is to include specific libraries that are unlikely to be on most target systems. So again it has a bloat associated with it, and also security risks if the Appimage is running insecure older libraries. Appimage can be in a sandbox but doesn't have to be, unlike Flatpak where sandboxing is mandatory - which is a security concern. Also Appimages are standalone and need to be manually updated individually while Flatpaks and Snaps are usually kept up to date via an update system.

I used to use PPAs when I was still using Ubuntu and Mint. Now I personally use Flatpak, and rarely Appimages, and occasionally apps from the OBS as I'm on OpenSuSE Tumbleweed. I don't bother with snaps at all - that's not to say they don't have value but it's not for me.

Edit: in terms of permissions, with Flatpak you can install Flatseal and manage software's permissions and access per app. You can give software access to more locations including system level folders should you need to or all devices etc for example. I assume you can do the same with snap but I don't know how.

Also you can of course build software form source so it runs natively , if you can't find it in a repo. I've done that a few times - can be fiddly but can also be easy.

A ppa is a repo. It’s Ubuntu stuff, and there’s no reason to work your ass off for Ubuntu for free. They’ll just shit on you and claim that snaps are great (they’re not)

PPAs are a nice idea but a terrible design. They work well as long as they are kept up to date and they don't overwrite distro packages. But in practice as you've noticed they tend to be abandoned after a while, and they don't respect the rule to not supersede original packages. Together these two faults lead to terrible consequences, as time passes they corrupt your Debian/Ubuntu dependencies and lead to unsolvable situations. Basically your system reaches a dead-end where it cannot upgrade anymore (or only partially, which makes things even worse).

Aptitude has a very smart and determinate dependecy solver that can recover a system from this kind of situation but it usually involves uprooting most of it by removing and reinstalling a huge amount of packages, some of which are essential. It takes a long time, if anything goes wrong you're screwed, and you may end up with older packages than what you had installed, which may cause your user data for those apps to not be understood anymore, leading to malfunctions or crashes. So yeah it can be done but at that point you might as well do a clean reinstall.

This seems as good a place as any to point out that I just perpetually have problems with flatpaks and snaps. Appimages less so but I wish they were better integrated.

Yes I understand why devs like these new packages. Yes I think that in the future they will be great. Yes they probably work fine for everyone else. I personally dislike them.

Because we have Flatpak. Also everyone kind of dislikes Ubuntu now especially the more technical users who historically maintaining the PPAs

Flatpak exists.

Because it's outdated. They are a lot of work and can cause package conflicts or errors, making the whole system less reliable.

If you need something, that's not in your package manager, then use Distrobox and create an Arch container, and use the AUR for example.
You can export the program after installing, and it integrates better into your system.

By doing that, the devs have to do the work only once and you will have less problems.

Most people I know just use Arch Linux and the AUR. It seems to be the easiest system around for maximal package support and it's well maintained.

I used to crash my Debian and eventual Ubuntu distros with regularity due to outdated PPAs. It was such a headache, and it’s why I still put my /home directory on a seperate partition just to make a reinstall safe for my personal files. I thought I didn’t like Appimages and their bloat until Snap came along. I hated Snap so much it convinced me switch distro’s again. Now I’m on Pop! and I love Flatpaks by comparison and now think Appimages are alright…

It’s 10+ years later and I still irrationally worry about crashing my system due to outdated & conflicting source dependencies. In hindsight the problems with PPAs clearly had a lasting impact on me.

Because they only work on one distro/package manager.

Distributing software is simply transitioning to work in a distro-agnostic way. It's only a matter of time until distros start updating flatpaks along with system packages. Many already do.

And some apps distributed as appimages self-update. (RPCS3 for example)

Not to mention that Ubuntu itself has basically ditched apt for snap.

whenever somebody brings up some terribly ancient Debian/buntu distro with outdated packages we end up having them use a .deb instead since the ppa is long gone and it's been fine. wild that they're often stuck on 4 year old packages though

I used ppas and then noticed the updates take forever and start failing as those ppas don't exist anymore. I switched to NixOS to eliminate having to deal with this. NixOS packages perfectly integrate with your system and you can install almost anything you need, even networking software and other things that need root. For everything else you can package it yourself, and nixpkgs will accept your pull requests

They were a bandaid solution to a problem that Flatpaks and Snap fixed.

the only person i'd trust for ppas is ondřej surý

When I was using Debian I found I could generally get the latest version of software I wanted from Nix if it wasn't in the main Debian repos, or was outdated. Nix works quite well on any Linux distro - it doesn't interfere with the rest of the system.

They are Ubuntu only and need to be kept uptodate to Ubuntu.

snaps (and if installed, flatpaks) should integrate very well into an ubuntu system. Does ubuntu really not update flatpaks and snaps through the normal update manager or whatever? Fedora definitely does.