Plus all those dynamically typed languages which are intrinsically built on the concept of generics (JavaScript, Perl, PHP, Python, Ruby). /sarcasm Nobody uses them because nobody needs generics.
They are intrinsically built atop generics. Duck typing is row polymorphism. Dynamic languages often depend upon that flexibility to operate—and they enable it by allowing everything. Static languages without polymorphism are at a low point in that trade-off space since they restrict useful operations and provide no way to express the invariances needed to recover that flexibility.
