One important issue to consider is that, by reducing functionality and locking down things like multi-tasking, Apple got focus on their innovative UI.

I am not an iPhone fan, but I must admit their user interface was far more intuitive for non-IT folks, and it is still hard to beat in this aspect. Nevertheless, I still don't recommend mobiles like N900, Android or iPhone to any friend/family who doesn't have basic computer knowledge. Even someone with basic knowledge sometimes does not have skills to do a simple software installation, so there is a lot to improve in the UI area if mobiles vendors want to increase their sales.