> things like intelligent defaults
Can you give a concrete example of a problem you encountered while porting 2->3 code caused by a poorly chosen default in 3?
> compatibility features and libraries
You mean like `lib2to3`? Or all the backports 2.7 got, e.g. what's listed at https://wiki.python.org/moin/StandardLibraryBackports ? Or the `__future__` system? Or third-party support like `six` (still immensely popular, though presumably only in CI)?
> the print statement (which could have coexisted with a print() function)
No, it absolutely could not have. Not with the same name, and making the name refer to the function was the point. The print statement syntax was inelegant, quirky and confusing. For example, parentheses can affect the meaning in unusual ways:
$ py2.7 -c 'print (1,); print 2'
(1,)
2
$ py2.7 -c 'print 1,; print 2'
1 2
> python's developers seem to have demonstrated tremendous contempt for the users
I don't understand how you have come to infer such an attitude. Any suspicion that they are introducing breaking changes on a whim will be immediately quashed by reading the discussion behind any of those breaking changes. (Not to mention what happens with the rejected proposals.)
> and avoid introducing breaking changes that multiply pain across an entire user base.
What breaking change was introduced in Python 3.x during your history of using it that caused a nontrivial problem for you? How many years do you believe you were given to account for it?