It's a nightmare to maintain compatibility with 2. Also you can't use any new features only because some lazy ass developers don't want to move. You have a leg

It's a nightmare to maintain compatibility with 2. Also you can't use any new features only because some lazy ass developers don't want to move. You have a legacy app that you don't want to convert? Fine, use legacy modules, they won't suddenly disappear. You can even user python2.7 after 2020. Want to use something new? Why also not use more recent version of the language.