You haven't been around iOS long enough then if you think that iOS 6 is bad about backwards compatibility. iOS 5 was FAR FAR worse. In fact iOS 5 makes iOS 6 look like the poster child for how to do it right. Seriously going from iOS 4 to 5 was a nightmare for a lot of apps. It took developers MONTHS just to figure out why their apps were crashing because the changes were so radical. With iOS 6 it has been mostly just a recompile and/or take into account the new resolution if they even needed to.
I have 197 apps installed under iOS 6. None of them failed when iOS 6 final was released. During the beta tests of iOS 6 only 1 of them failed.
Now if memory serves I had over 200+ apps under iOS 4. During the iOS 5 betas easily 30+ failed to even launch. At iOS 5 final release those same 30+ failed to work until they were update by the developer.
But an even better example would be Com2Us. It took them 6 weeks and 5 updates before they finally got Tower Defense - Lost Earth fixed 100% to run under iOS 5. And they are a huge developer house. In fact they released their first iOS 5 update of the game, with permission from Apple since they were a major partner, a day early so that it would be ready when iOS 5 went live. The reason I remember this so clearly? I had waited 4 months to be able to finally play it again because I had been testing the iOS 5 betas. Was really disappointed when iOS 5 final was out, I got the update and the game still crashed.