Apple has managed to maintain consistency and provide a level of experience over the years by tightly controlling the platform. This is just another manifestation of that. Look at the App store, the fact that you have to use hacks to get OS X running on a PC or that you buy Apple computers with OS X being pre-loaded as examples of that.
If you don't like the closed platform you can grab a PC, but I think this is just how Steve Jobs does things -- he likes to have as much control as possible so that Apple can deliver a certain type and level of experience to users.
Macs are wide open. Apple creates the default user experience, but you're free to develop and run any software you want without begging for permission. Apple's total control over the iPhone/iPod/iPad platform is a change for the worse.
If you don't like the closed platform you can grab a PC, but I think this is just how Steve Jobs does things -- he likes to have as much control as possible so that Apple can deliver a certain type and level of experience to users.