The number doesn't know how to loop. `100.times` returns an enumerator that can then be iterated upon. In real code, that particular method doesn't get used all that much, but its existence tells you nothing about Ruby's design.
Why shouldn't every single object have a 'nil?' method? It can be very useful. Think about operating on a collection of objects with `map` or `collect` or whatever your favorite language calls it. No need to write code, just send the `:nil?` message to every object, which you can do with one line.
You're right that "everything is an object" is not the most performant way to build a runtime, but it suits the purposes for which Ruby was designed very well. Just because you don't value those priorities doesn't mean others do not.
