Can you name a major market where the majority of users own the same exact product? People like different cars, different appliances, different houses, etc. How do you expect the phones to be different?
Phones aren't like cars, they are more like computers (and becoming more so).
You can pick the abstraction level to suit the argument.
They might be able to do a lot of the things that a "real" computer does but you don't have the power to treat them like regular computers. You can't easily put a new OS on them, write software for them without going through a central market place, etc. Apple obviously has this vision, but it's becoming clear that Microsoft shares it, at least for Windows Phone 7.