I used to use an old version of Quicken for Mac (this was back in the MacOS 10.2 days). It was "finished" in that it did absolutely everything I needed and there were no bugs that affected me. As time marched on, Apple switched from PowerPC to Intel which was fine because they had technology (Rosetta) which allowed me to run PowerPC applications. Then they dropped Rosetta, so now I had to choose whether to upgrade MacOS or continue to use Quicken.
I now use software called Banktivity to replace Quicken. Much like Quicken, Banktivity is "finished" as far as my requirements go. The version I have is Intel-only and Apple is switching to Arm processors. How long will Rosetta 2 last before it's pulled and I'm forced to choose between upgrading my OS and using this software?
I think there are similar things in the mobile world too. I think Google requires apps to use a minimum API version to maintain a listing in Google Play. I believe Apple does something similar with the App Store too. So short of regularly recompiling, testing, and publishing your app, everything in the stores has a finite lifetime.