What I mean is that it is much more than "you may only use Objective C to develop on this device". You also haven't thought this through. It has many more long term implications than the language choice.
And we have a disagreement about what viable mobile platform means.
For example, "Gameloft sells 400 times more games on iPhone than it does on Android."
http://www.pocket-lint.com/news/29757/gameloft-cutting-andro...
There isn't much of a mobile games market outside the iPhone. Unless you want to develop children games for the DS. And then you would need to wear a suit to sign a contract with Nintendo. And guess what, they don't sign more than X contracts a year, where X is a very low number. So you could be out of luck.
The point is that if the iPhone is the most lucrative platform now, it is not in the best interest of the developer to put their eggs in only one basket. And markets change. So they should create demand in parallel in other devices too.
But to port to other devices takes time and money, two scarce resources, as you now.
One way they could be less dependent on the iPhone with minimum investment is to use a compatibility layer like Unity. Unity already works on the Wii, and will work on the Android and Xbox soon, with windows phone probably not far away. But with the new rules, that is not a solution anymore.
Also, it is ironic that Unity will work on Xbox but not on the iPhone. Don't you think?