Refusing to break backward compatibility is how you end up with some of the uncomfortable anachronisms that can be found in PHP and MySQL and other things. A la

Refusing to break backward compatibility is how you end up with some of the uncomfortable anachronisms that can be found in PHP and MySQL and other things. A language that did backward compat arguably well is Java but it had to be extremely conservative, a property that has made it popular to replace wholesale with languages that are nothing like Java. If it helps, you can convince yourself that Py3 is a different language that just happens to be very similar to Py2, and that Py2 needs new maintainers. This happens all the time.