I'm not sure that the "quality" of the majority of the apps in the app store is very high anyway. There are certainly high quality apps, and I'd bet dollars to donuts that they are written in one of the approved languages.

But the reason the iPhone became popular is not because there was a very high quality app version of wolfram alpha or a gold game, but because there were reasonably good quality apps (at a good price) that scratched relatively small, (dare I say it?) long tail, itches.

You can be relatively sure as a new iPhone owner that you'll be able to find your fishing lure guide app, or your app to order emergency socks or whatever. I'm willing to bet that lots of those apps were not written in one of the approved national languages of the Union of Soviet Apple Orchards.