Take a look at this compilation of the Top 100 movies of 2011 and where they are available (or not) to legally stream from online. This isn't even a complete list as the studios still frequently will only put the standard definition version of a movie up on iTunes when of course an HD copy is available. Also, support for iTunes Extras is nonexistent or weak.
This is why Hollywood is losing money to piracy. There will always be people that just don't want to pay for content, but the big attraction of piracy to honest people is that it feels like everything is available. It's a better service. Seems very analogous to Napster before Apple convinced the music labels to license a very high percentage of their catalogs at reasonable prices for download. Then you have the studios trying to launch their own streaming service, while continuing to cripple the established services out there.
Hollywood has crippled the legal download sites with this quagmire of availability, SD vs. HD, and little to no price break over buying a manufactured physical disc. Clearly the studios are trying to preserve buying physical discs or make at the least make it more enticing than downloading, but it's just not going to happen anymore. The tide has turned. Add to that the complicated "windowing" that studios try to enforce on home viewing rights, and a lot of consumers just check out.
This should be obvious, but don't the studios get that most people can't and won't keep track of the studios windowing schedule? Once you market a movie, if people want to watch that movie and they can't get it legally and at a fair price, at some point they are probably going to investigate pirating because it bypasses all the studio bullshit.
I'm not supporting pirating, but it's not hard to understand the appeal beyond just not paying for stuff.
I tried to watch Game of Thrones and this is what happened cartoon from The Oatmeal perfectly captures the problem.
Andy Ihnatko perfectly captures what I generally try to practice regarding the byzantine content access rules, find something else to do!