I'm sorry, that's absolutely bullshit. In fact, I wish we had left everyone who complained behind—the python community would have been happier and healthier for it. Absolute crybabies who wanted to be catered to without caring for how intractable the problems with python2 were—e.g. dealing with unicode was a royal pain in the ass, and the bytes/string divide completely fixed it. IMO, it was the best-executed breaking change I've ever witnessed in a language.

In comparison, e.g. Scala 2 -> Scala 3 was an absolute nightmare—it just didn't have the same vocal wailing from maintainers in the community (or, I suppose, a fraction of Python's popularity to begin with).

Being to aggressive in breaking stuff gets you a shitshow like Node.js or Ruby. Long-term source code compatibility is a very useful feature for open source and a sign of a mature eco system. Feel free to add stuff, but once it's part of a stable release it has to be maintained long after a "better" way to do it comes along.