To make apps for Android you can take a 15 years old PC from the dumpster and a 5 years old smartphone that your cousin threw away and you're done. No other payment required.
To make apps for iOS you need to have a supported Mac and you need to have a supported iPhone. The OS upgrade treadmill means you need to buy a new one of both every 5-6 year (or used every 2-3 years). Finally, you need to pay a yearly $100 development subscription forever. (When you stop paying, your apps are unpublished)
Also: on Android you share the source and anyone can compile it even a decade after release. On iOS compiling old source is much more difficult as you probably need to change or fix to the updated apis