A bunch of low-reach languages have true parametric polymorphism. A bunch of common languages have polymorphism that may be parametric or may be bounded by runt

A bunch of low-reach languages have true parametric polymorphism. A bunch of common languages have polymorphism that may be parametric or may be bounded by runtime type information checks, and you can't tell the difference from the types. Neither of those contradict my assertion that most programmers have never done work in a language where the type system can make guarantees that they can trust.