(Shrug...) The tools are different, that’s all. Remember also that Moose is designed to provide a pragmatically acceptable object-oriented context with regard to a language (Perl) that does not intrinsically have one, whereas the Python features that you describe are native to the (current versions of the) language. Both languages are great. I use both of them all the time.
But this is apples vs. oranges.
The only directly-comparable relationship that I can think of would be to “the not-here-yet language commonly known as Perl 6.” As things stand here, Moose is doing as well as it can ... which is, pretty well.