Why were ES5 Object methods not added to Object.prototype?

Question

ES5 added a number of methods to Object, which seem to break the semantic consistency of JavaScript.

For instance, prior to this extension, the JavaScri

Answer 1

the JavaScript API always revolved around operarting on the object itself;

This is not correct. E.g. JSON and Math always had own methods. Nobody does such things:

var x = 0;
x.cos(); // 1.0
({"a":[0,1],"p":{"x":3,"y":4}}).toJSON();

There are numerous articles on the web about why extending Object.prototype is a bad thing. Yes, they're about client code, but maybe this is bad for build-in methods also for some points.