One of the problems with Python is that they almost encouraged writing code in 2 and porting it to 3. Also: Python 3 is almost a complete different language.
It would be the same when PHP6 would use a + as string concatenation. Such changes would turn it into a complete different language.
Somebody who has used both will notice that Python 3 is syntactically and semantically almost identical to Python 2 in most respects. The main differences are in terms of removing redundancy, removing outdated features and functionality, increasing consistency, vastly improved Unicode support, and standard library improvements.
A developer with Python 2 experience should be able to pick up Python 3 in about 30 minutes, at the most. That's not what we'd expect were Python 3 "almost a complete different language".