[ahofmann]

PHP watched the absolute disaster of python 2 to 3 version upgrade and rightfully decided that it will be as much backwards compatible as possible.

PHP 10 with a clean slate is a cute idea that would wreak havoc. Perl, or whatever it is called now, tried this and it was a total disaster.

[zelphirkalt]

I personally never perceived Python 2 to 3 as a disaster, and the language has come out better on this end. It would have been a disaster to keep all the cruft of Python 2 forever and keep writing software in it. When Python 3 became stable, I simply never looked back at Python 2 again. Sure, many libraries had to change a bit, to accommodate Python 3. But any sane project would start with Python 3 anyway, and over time Python 2 support would simply fade away, as fewer and fewer people use it. Maybe during some transitional time people had backports of security fixes for Python 2, but in this day and age I wouldn't actually bother with that any longer. Whoever still runs on Python 2 has made a decision to do so, accepted responsibility for not transitioning and has no one but themselves to blame.

Overall they actually did a pretty decent job to transition from Python 2 to 3. Many people didn't have any issues at all, and simply used the new thing instead of the old thing.

Python's language design in itself is debatable of course, but it certainly is better now than with Python 2.

[ahofmann]

I was maintaining some debian servers back then, and for more than a decade there was great confusion around python. What you describe as "Sure, many libraries had to change a bit" was a major pain in the butt for many people for many years. I'd describe this as a disaster. The "just start a new project"-mentality is not what happens on servers and companies of the world. They support stacks, that are literary decades old.