Well arguably the definition of inheritance there doesn't meet the poster's idea of inheritance. Prototype 'inheritance' is a kind of delegation and some prototype OO languages make that explicit by using different terminology (Self says 'delegate' and not 'parent' for example).

But then arguably in class-based OO languages, classes don't "inherit" either and really just delegate to other classes.

(FWIW I wrote a big chunk of the prototype-OO article on WP at one point. Not sure how much of that text still exists)