I really hope not tbh, once you break that seal it will consume the entire language into nested anonymous function soup without all the facilities JS has accumulated over the years to mitigate it. Python is an iterator based language and it leads to some very nice code if you design with that in mind.

It's really incredible how much such a small feature in the grand scheme of things `(function() { })()` influences all API and library design. Right now passing around functions in Python is ugly and reads as such which is enough of a deterrent for most people.