It seems that content providers have already ruled out all the the iPad killers coming from Samsung, Dell, etc... I'm sure those companies will offer a better price as soon as they get their "iTunes killers" in place. Content providers can pass on Apple's demands if they feel they are too high. The iOS is not the only way to distribute content available, web browsers and print still remain options. Yes the future will eventually make the tablet or should I say Pad the best outlet but we are not there yet.
I read a blog that basically argued this was a sneaky way to get publishers to move their content to HTML5. The argument was basically that SI (I think?) was able to create an HTML5 web-version of their magazine that very closely replicated the feeling of an app. If providers want 100% of the pofits, they can publish to the web and control the payment. On top of that, ANY tablet (or web browser) would have access.