That's not entirely accurate. Google adds tons of value post-sale to Android devices. Most of that value just happens to be through app updates and new apps, no

That's not entirely accurate. Google adds tons of value post-sale to Android devices. Most of that value just happens to be through app updates and new apps, not OS updates. To muddy the waters even further, some of the apps that Google updates (e.g. Market/Play Store, Music, Maps, etc.) are treated as part of the OS on the iOS side of the fence. Moreover, Google, quite understandably, is moving even further in that direction (e.g. Chrome Beta shows even browser updates moving outside of the core OS). I'll separately add that once you go outside of what Apple considers the OS, they actually do a relatively poor job of supporting older devices with their new apps (e.g. Siri, iPhoto, iMovie, etc.) compared to Google. Often, the iOS hacking community even demonstrates that the barriers involved aren't technical.