It&#x27;s not necessarily about breaking or maintaining backward compatibility that matters here. It&#x27;s about how supporting two similar looking yet ultimately incompatible versions creates confusion for new users, driving them away.<p>This is the same issue facing Perl (although the Perl situation seems more dire) WRT Perl 5 vs Perl 6. For Python maybe the benefits of keeping Python 2 alive for large users offsets the harm of any confusion, I have small projects (all in Python 3) so it&#x27;s a rare annoyance rather than a deal breaker.