Just because you can root and tinker with something doesn't mean you have to. Millions of people use Android phones without ever having touched a third party rom (or even have the knowledge that they exist).

Additionally, Apple allowing a user to install a browser with a rendering engine other than webkit does not preclude a completely different user from experiencing the "Apple experience". The default experience will be the Apple experience.

I really don't understand this common sentiment that more freedom for a user to use a device in the manner in which they want to somehow takes away the freedom of others.