The biggest problem with allowing third party company to write code for a platform - in this case the iphone is Crap Code!
Apple has it down pat and they know it, they make the hardware and the OS, their platform is stable. They don't want their iphone being polluted with poor code. It is really essentially a CVS type system. company A builds a program, and submits it to Apple. Apple tests, if they approve the code it is then purchasable through itunes...
Dan