The problem is apps raising the minimum iOS version. Apple usually doesn’t backport new APIs, so developers are eager to bump it up to use new APIs/frameworks. Similar thing is now happening on macOS. A lot of apps require macOS 11/12, which is pretty crazy compared to how desktop software used to run on much older versions of OSX.
Yea, I've seen apps that required >= the latest OS version available! Totally unacceptable. From a marketing POV alone, why would you just close the door on a significant % of your market before they even look at the product?
When I had a job writing mobile apps, I tried to "fight the good fight" by keeping our minimum version as low as possible, but everyone up the chain from me pressured us to increase it, especially software engineering, because it was "too hard" to maintain backward compatibility with older versions. Even though maintaining compatibility usually just meant a handful of if statements.
This is a huge problem if you use heavily apps and must use the most recent version. I've got a 6+ year old iPad pro that just works...I haven't noticed any apps saying I can't install them, although I guess it is still supported by iOS's latest version.
