Isn't it XCode that blocks you from developing for older versions at some point?

Daedren · on Jan 17, 2024

No, Xcode requires you to have an up-to-date MacOS to develop, not iOS.

However, developers are strongly encouraged to raise their apps' minimum iOS versions since Apple does not backport any APIs to older versions, any new thing presented at WWDC is only for the new iOS version. This also applies to bugfixes in some cases (SwiftUI).

So as a developer you either stagnate your knowledge or keep moving forward. Google does backport many APIs, so the issue isn't as problematic on that end.