I honestly can't think of a single reason that studios aren't handing cheaper content over on a silver platter.
You make a number of good points so I'll just offer feedback to this one thing. The Movie/TV Studios don't want to get under Apple's thumb the way their cousins in the Music industry did. With music, Apple flexed dictating everything such as how much their product should cost. Every single- new or old, good or bad, hot or stale- all one price, as decided by Apple, not the owners of those products.
Apple quickly took dominant share of the space. Traditional music outlets where the owners of that content had more say in matters like how their product should be priced were run right out of business. Before long, Apple became the 64000 LB Gorilla that they HAD to deal with... on Apple's terms.
Now the industry must cater to Apple. Options they traditionally controlled themselves were sacrificed.
The movie/TV content owners do not want that history to repeat with their content. They don't want Apple to dominate their space. Of course, it would be a cheaper, more efficient form a distribution. Of course, it could be a more profitable form of distribution (if they get to have a say in how their content is priced). Etc. But they just don't want to cut their own throats to help Apple grow.
The music industry was left with little choice but to turn to viable Apple competitors like Amazon and take even greater hits in the short-to-medium-term by offering Amazon, etc better pricing to try to pull buyers away from getting locked in with Apple. In cliché terms, they don't want all their eggs in one basket. And the movie/TV industry doesn't want to see that same scenario repeat with their content.
It's why Netflix, Amazon, VUDU, and many others get seemingly better deals for lots of video content in spite of what seems like the easy choice of just getting it all on iTunes at a fantastic price to sell more. Make no mistake: the Studios definitely want to sell more too... just not at a cost of giving the whole distribution channel- and thus power to dictate terms- to Apple. In short, the "greedy" Studios understand that giving into the temptatation of Apple now just puts them at the mercy of Apple later. They don't want to be in the same weak position as their cousins in the music industry so they resist the temptation (and work pretty hard to help others offer viable challenges to the Apple option).
The silver platter you perceive is actually tin painted silver. While it would be great for Apple- and for us as Apple product owners- the loser would actually be those Studios who would be taking the hit to make it great for Apple and us.
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Only if you're viewing an uncompressed source and your standard cable/satellite/netflix feeds, which is what the average user bases everything on, are far from uncompressed. Even at 720p an uncompressed streaming file on the ATV2 looks better than the standard HD signal from any of the above sources.
There's no uncompressed streams from any sources. It's all compressed albeit at varying degrees. Even over-the-air with an antenna is compressed. Blu ray is compressed. Apple iTunes content is all compressed. Home movies shot at 1080p are compressed. iPhone 4s video is compressed. It's all compressed.
Nothing is flowing to the

TV2 uncompressed. To some degree, it depends on fairly steep compression to even push a video onto a HDTV screen.
If you've seen 720p uncompressed, you must work at a movie studio or at a video production company with HUGE technology resources.