I think you may be conflating two things here: C#/Java/etc style static OO vs Smalltalk/Python/etc dynamic OO, on the one hand, and class-based vs. prototype based OO, on the other. IMO most of the good bits of JavaScript's object system come from it being dynamic, not from it being prototype based (indeed, JS and Python's object systems are very similar, except that Python has language level support for treating some objects as representing types).