Agreed. There is a vocal minority of people (academics mostly) yelling at how subtype polymorphism is broken and unusable. It certainly has broken aspects (with

Agreed. There is a vocal minority of people (academics mostly) yelling at how subtype polymorphism is broken and unusable. It certainly has broken aspects (with respect to equality) but by and large, it's extremely usable, intuitive and it enables powerful abstractions. The corner cases where it falls apart seem to be irrelevant for most uses.