The issue is that there isn't a service that can offer something that torrents do. Like petvas said, he and I would be more than happy to pay for a service that offered decent HD content. It doesn't have to be as good as Blu-Rays but something better than what iTunes calls HD (we don't even have iTunes movies or TV shows here...).
How can you keep talking down iTunes rentals as not being HD when you don't even have the service there? I and most others who have
actually tried it would have to say iTunes HD rentals are excellent quality. Not Blu Ray but it is certainly as good as or better than almost anything else referred to as "HD". And that includes Satellite TV and cable.
When it comes to internet streaming, iTunes is better in quality than other competitors like Netflix or Amazon and while there may be services like Vudu that let you stream at higher bitrates, they can't compete with the price and selection of iTunes. If your only standard for "HD" is Blu Ray then just say it isn't Blu Ray quality but don't say it isn't HD quality. But then, no one else is streaming upwards of 30mbps either.
Just like with digitally downloaded music vs CDs, it took some time but the quality has now reached the point where the convenience factor far outweighs any perceivable quality benefits of discs for most people. Most people aren't audiophiles or videophiles. Once the quality of the movie is no longer distracting (clear with no artifacts and blockiness), the story line becomes the focus and you just immerse yourself in the movie (like it should be) and that happens to be the same no matter which method you view your content.
With that being said, I use EyeTV for recording current seasons of TV shows which are automatically exported to iTunes and then immediately available to watch on my ATV2 with Home Sharing or on my iPhone 4 with the EyeTV iOS app and various other streaming video apps like Air Video. I use Netflix Instant Watch for older seasons, older movies, and documentaries. That makes up the bulk of my TV watching.
Then on weekends, movie night with the family, or when I just want to watch a good current movie, I rent it on iTunes. Great selection, high quality, and instant convenience. I have the Blu Ray disc option on Netflix but I just never seem to have time to mail them back on time and they sit here for weeks sometimes. And by the time we get the disc, we may not be in the mood for that particular movie.
I used to buy DVDs and BluRays but I converted all of them with Handbrake to play on the ATV2 and just don't buy any discs anymore. Nowadays when I want to watch a new release movie, I just use iTunes rentals on the ATV2.