If iPhone is the only phone available?

And it means no symbian, no android, no bada, no windows phone, no windows mobile, no blackberry, and no feature phones, what will the people who can't afford the expensive iPhone price? Will they steal an iPhone, or?

That's a stupid argument… It's not the only phone available. The market demands iphones for people who want to pay for them, and cheap phones for people who don't… And that will always be the case.

There will always be cheaper phones available, but if somehow, the iPhone becomes the only phone to exist, people would steal them (and people already do), but I think phones would become less popular, because people would find a cheaper communication method.