not going to happen. The main problem is that in the minds of consumers there is now 3 categories: a cell phone, an iPhone and a blackberry. So any "competitors" to iPhone just fall into the cell phone category, and thus get pretty much ignored by many people as not being anything special
Only 2 years late... The only way to dethrone the iphone is to innovate even more which is not an easy task.
...while Apple is already working on whatever comes next.
I've heard this song before.
And since 2001, I haven't seen any actually succeed (i.e. iPod killers from microsoft, iriver, cowon, sandisk et al), although there are a fair number of worthy competitors :)