I don't think the problem is from crappy apps. As the owner of the phone, it should be my choice to decide whether or not I want to install these apps. The problem is from Apple who doesn't let people do what they want with their phone.
Hopefully, there will be a way to sneak these apps around in the black market in a little less risky way than with the current jailbreaking. This seems to be quite a contrast though, I remember hearing somewhere (of course, don't remember where, now that it comes to mind, heh...the brain works in mysterious ways)
What I heard was that they would actually be allowing all the current unofficial 3rd party apps to be installed, but to warn beforehand and indicate they may be unsafe and cause instability. Kind of like how Windows does its driver signing and how it warns you when a driver hasn't passed the WHQL tests - you can still install it, it just bitches at you telling you all sorts of things that can happen
But, of course, that's a pipe dream and will never happen in a million years...it would just make the iPhone perfect, and instill a lot of confidence we've otherwise lost in Apple.
So it should be easy for the 'competition' (nokia, Samsung etc), to provide similar userface experiences and just open their platforms wide open and eat Apples lunch.
I wouldn't think twice about jumping to a better device regardless of the manufacturer.