Yeah, I think if your app is Facebook or Twitter or Google Maps, it doesn't really make a big difference. But Gameloft is clearly in a very different space.
I think Microsoft's claim that apps will not differentiate platforms will be true in the very limited sense that things like Facebook will be available at comparable levels of quality across most major smartphones. I think it's not true in the sense that development of creative new app ideas and of games in general will not commoditize unless there are significant changes in the structures of the WinMo (if it continues to exist) and Android worlds that would allow developers to have a reference platform against which to design sophisticated games.
Even besides Gameloft, one of the prominent things about the games on the iPhone are that there are numerous runaway successes by independents, both inside the industry (e.g. ngmoco which was started by veterans but as a new project) and from relative outsiders (iDracula, Soosiz, etc). That buzz of excitement around development is not going to commoditize unless it dies out on the iPhone (in which case I guess conceivably it could in the sense that no one would have any creative games on their devices). I don't see that happening though.