By the time you've written a Python that has all explicit types in it, and harvested the speed advantages the interpreter can have when it can count on that, and all the other cascading changes that would result, and the fact that you would discard 100% of all previous modules both Python and C, you might as well just start using one of the existing statically-typed languages that already has a mature ecosystem.
Python should be working on being the best Python it can be, not being an adequate Python and an inadequate bodged-on static language on the side.