OTA isn't uncompressed. There is a finite amount of spectrum each channel gets (6 MHz I think) and that is a big reason the transition to HD took so long. HD was first experimented with in the '60's but it wasn't until digital compression came along that an HD signal could be effectively compressed down into the same amount of bandwidth as an analog SD signal. Channels (from OTA and cable) could have better IQ but many times they will spilt a single channel into multiple sub channels (ex 13.1, 13.2 13.3, etc.,) which degrades quality but lets the distributor send out more content which means more ads which means more revenue.
A big advantage streaming has is that the Internet is a much more malleably distribution medium than baseband video signals. YouTube, for example, went from streaming 320x240p in '05 to 1080p in 2009 and these upgrades were basically invisible to the end user. OTA can only utilize better compression to stay within the allotted bandwidth where as streaming can benefit from both better compression and increased bandwidth.
And no one is disputing the variable quality of media that reaches the end user though in your specific example what do you expect from a DVD? It's a video standard with roots in the 30's using compression that was cutting edge in 1996.
With regards to poor transfers of older films, it comes down to money. It takes time and money to do a quality restoration and the distributor footing the bill isn't going to spend more on the restoration and distribution than they think they will make in profit from selling the end product. I doubt 4K will be any better because the bottom line is still about revenue and Joe Average consumer is fine watching a 4x3 movie distorted or enlarged to fill a 16x9 TV because they don't like having the bars on the sides of the image. Quality is not a primary concern (if it was MP3s would not be central to a watershed moment in media distribution).
There are also limits to the human vision system and I'd wager that given average eye sight, average viewing distance and average HDTV size the vast majority of viewers wouldn't be able to tell the difference between a 720p signal and a 1080p signal let alone the difference between 1080p and 4K. For 4K people will probably need TV's the size of walls or be sitting so close they can touch the screen. People will be them though, whether they can actually tell a difference or not, because big is better and to many it's about keeping up with the Jones'.
With that being said Sony is releasing a line of Blu-rays of movies that were mastered in 4K (the final image is still 1080p of course) and I think Sony is working to master all of its modern movies in 4K so maybe there is a light at the end of the tunnel for those desiring a more pristine viewing experience.
Digital OTA is pretty much uncompressed. Analogue is another story. Digital OTA is vastly superior to any Sat or Cable. As for Internet streaming, it beats that as well.
I'll stand by my statement that 4K of any movies will be a hit and miss affair exactly like DVD and Blu Ray. The argument about what people will pay is rather silly as Criterion as mentioned does a brilliant job and its market is very select unlike the typical studios.
As for Sony, of course they love 4K as they are trying to get their studio and hardware profits UP. This is the same Sony that has a PS3 that hardware-wise should be able to play various media files but Sony refuses to support them because as you gather, it is a conflict with their own offerings.
Hope you enjoy the 4k and truly hope they do a great job with it. - I just wont hold my breath as Sony and a couple of others will have a few good titles to parade around and the rest will be exactly like Blu Ray and DVD - hit and miss.