Apple, Google, Amazon, etc. are trying to create captive audiences. This works particularly well if the government steps in to make it financially prohibitive to operate outside their spheres of influence.
Apple, Android, and Amazon's b@stardized Android that runs Kindle will push the masses to "legit" sources for news, entertainment, etc. That means Facebook, Wall Street Journal, CNN, etc. Not Free Republic, Drudge Report, and Rush Limbaugh.
The goal is to make it difficult to go outside of these acceptable "mainstream" sources of Internet content. The few who will jail break their devices will be able to access that "open source" blogging content you refer to...assuming those bloggers haven't been regulated out of existence.
I don't believe this captive audience plan will work...just that each of the big players is trying to grab a large chunk of the online sheeple and make it difficult for the flock to go elsewhere.
The only good thing about this is that it will put jackasses like Perez Hilton out of business.