This kind of neglect for backwards compatibility is honestly why quite a bit of free software is failing, and also why quite a bit is not that understands it.

Like the fiasco with Python3 and Wayland. It's so clear the developers just thought “Wow, people will just switch” not realizing how much people demand an absolute drop-in replacement and then maybe later you can think of slowly deprecating features to discourage new users from adopting them. Rust realizes this with editions. Yes, it's a big investment for them to continue to support it, but the alternative is that Python library maintainers now have to have this big investment themselves because they have to maintain like 6 different versions of the same library because Python doesn't understand the value of backwards compatibility. z/OS still supports 50s COBOL frameworks and for good reason. No one is going to rewrite that.

These developers when you talk about them really do not seem to understand that people aren't jumping to rewrite code or maintain different versions at the same time and very often even call them “lazy” for not doing it like they're not using their time for other things. Say you're a company, and you can pay a developer for his time:

1) Have him develop new features that make you more money.

2) Have him fix bugs that cost you money.

3) Have him rewrite existing code that will do nothing new, and will probably introduce new bugs again so you can later go to 2.

Which is more attractive?