[has2k1]

Well, they have to balance (dis)pleasing both the old users and the new users. Not everyone will be happy, even those that may benefit later on have no way of voicing opinion based on the satisfaction that is yet to come.

On the human side, people do not like to stare at glaring mistakes all the time, if they can do something about it -- having weighed the cost associated with the change.

In 20 years if python is still a thing, it likely will not be because it was designed right from the get go. It will be because it changed enough to stay relevant despite the fact that some changes may have left incompatibilities in their wake. Users have to live with that.