A price increase just isn't going to happen, at least not just because of iOS. iOS simply doesn't represent a great enough percentage of these companies' customers to make that viable.
Amazon, for instance, is not going to hike their kindle book prices by 30%. They're not going to screw up the rest of their kindle business just to play on iOS, especially when they have to compete with Apple (who obviously don't have to worry about this), the B&N Nook, and the Sony eReader.
Though Sony and Barnes and Noble are in the same boat. I suppose Amazon thinks its win/win. Either they actually get to have everyone else raise their prices 30% and get a 30% cut on everything, while increasing their own sales due to cheaper prices, or they don't have to compete at all on iOS.
I can't imagine this would hold up as legal though. It's just so over the top.
At any rate, I've gone from excited about the iPad 2, to no wanting it if it were released today just within the past 48 hours. I will not support companies or individuals that act as thugs if I can help it.
No, they cannot do this:
All we require is that, if a publisher is making a subscription/purchase offer outside of the app, the same (or better) offer be made inside the app, so that customers can easily subscribe/purchase with one-click right in the app."
If you sell something outside the app that can be used inside the app, you will also have to offer it via in-app purchasing.
Which means everyone would have to raise their prices by 30%.