I am just imagining this, or did it feel like 10-15 years ago breaking changes were a big deal, and companies went out of their way to provide an upgrade path. Now my flutter app from 3 months ago won't even compile.

The major platform companies have different historical attitudes that haven’t changed much.

Microsoft: We told you what not to do, and you did it anyway, so we’ll put code in our OS specifically to keep your app running.

Apple: We didn’t tell you that was OK to do, and you did it, and our latest cool stuff broke your app. Over to you. Also, we didn’t mention this earlier, but no more 32-bit apps next year, sorry.

Android: We try to keep your app running, for a while, but TBH a lot of the platform comes from manufacturers who only care for about 18 months. Let’s all just try to survive.

A depressingly accurate summary...

not just 32bit. No more powerpc (and soon x86), no more system 7/8/9 apps, etc. It's now a long tradition.