I think you missed that the App Store is an iPhone afterthought -- the original, still supported, intent was to support HTML5 apps installed to your home screen.
You can write your own software, run it on any iOS device, share it with others, even sell it without anyone's permission.
Here is a PacMan style game, for example:
http://mrgan.tumblr.com/post/257187093/pie-guy
If that's not "hobbyist" friendly, I don't know what is.