It's a common issue at this point: a game releases, gets years' worth of updates and DLCs, and then eventually the developers move on to developing a sequel. The sequel comes out and... the depth and amount of content is nowhere close to what players have just been experiencing in its predecessor. The sequel may have many of the quality-of-life features that didn't arrive in the predecessor until later updates, but it simply can't launch with a full game's worth of content plus years of DLC's worth of content. It only gets worse for games that support modded content, too, because they'll have years' worth of mods on top of the developer-created content.
We've seen this a lot already: the Civilization series is infamous for the sequels not living up to their predecessors until they've had years of support themselves; Crusader Kings 3 was seen as lacking in long-term replayability for passionate fans of the series; Destiny 2, upon release, was seen as shallow and sparse compared to the first game; and, recently, Cities: Skylines 2 developers spent the lead-up to the game's release trying to reel in expectations because they didn't want fans to expect the game to have comparable amounts of content to everything that's available for the first game after eight years of post-release updates and DLC.
To compound this, many of the games that benefit from extensive post-release support are less story-focused games. They often offer a mechanical foundation and a sandbox wherein players can create their own experiences, stories and lore - Civilization has no plot, nor does Cities: Skylines or Crusader Kings. They're similar, in fact, to tabletop RPGs - like Dungeons & Dragons - in that sense. And they share another issue with tabletop RPGs: sequels sometimes just aren't necessary. When there's a new story to tell in an existing world, or for an existing character, it obviously makes sense to make a sequel and tell that story. But if the game is more of a mechanical foundation that's already sound? Well, major overhauls to that foundation are a reason to make a sequel, but sometimes it can just feel like "reinventing the wheel" for the sake of releasing a sequel, not because it's necessary or because it improves anything.
It feels to me like a problem that will only become more and more pronounced as more games opt for live-service models or extended post-release support, too. Can anyone think of any examples of games that had extensive post-release support through updates and DLCs where a sequel was then released that wasn't seen as disappointing or a step backwards?
Factorio's 2.0 update does have a paid DLC to go with it, so it'll definitely pay for itself! The free update is going to have the more mechanical balance changes and the quality of life stuff, while the DLC will have the new content (like space platforms, other planets, etc). I agree that it's definitely a good approach for them to take - somewhere between an expansion and a significant enough update/overhaul that they can market it as similar to a sequel. Factorio, especially, is in a state where it certainly doesn't need too significant an overhaul - what's there works very well, and there's no need for them to reinvent the wheel.
Path Of Exile was planning on taking a similar approach with their 4.0 update - a major overhaul/update to the current game, and marketing it as Path Of Exile 2. The plan was to have a new campaign with new playable classes, but to share an endgame with the current game. They've since decided to scrap that approach and make it a full-blown sequel, though, which I think is probably a good approach for them to take. The current game (which I've played an awful lot of and do very much enjoy) has quite a few fundamental design limitations and balance issues and I think giving themselves a tabula rasa without all that mechanical and technical baggage is a good idea.
So I suppose Path Of Exile 2 might well end up being the first example (that comes to my mind) of a sequel that doesn't feel too disappointing in that regard. Of course, that's speculation on my part, but I do think what they've shown of it (there were demos that a lot of people played at their convention earlier this year) and the mechanical deep dives they've done seem promising. I think a lot of the content from the current game - or at least the mechanics for the content - will be brought over to the sequel, too, so I don't think it'll have the issue where it feels like a brand new game that's lacking in content compared to its predecessor that's had 10+ years of live-service content.
Absolutely. The biggest issue I see with this approach is it makes it more and more difficult for new players to find a jumping-on point the longer a game goes and the more content is added to a game, but it's certainly a better approach for the more invested fans. It means the developers need to ensure they avoid the game getting too bloated, too, and to avoid power creep in whatever form that may take for their game. I suppose those are the tradeoffs for not needing to remake everything from scratch for a sequel, though!
I think this deceptively difficult to answer, and there are quite a few perspectives to consider. Of course, it's easy to argue that if I think, for instance, C:S1 is a great game and I think C:S2 is disappointing, I can just continue to play C:S1 and that's fine, but I think in reality it's a little more complex.
So generally I'd say: yes, it's bad for games as an art form and as a form of entertainment, both on a micro level (specific games can suffer for it) and on a macro level (the industry can be negatively affected by it).