So many posts in this whole thread basically lay blame at cost- cost of videos, cost of hardware, etc. There's other cost-minimizing wants too like (Apple should) start a Netflix-like service for their videos, an Apple Video service that works like Apple Music, and/or Apple should just buy Netflix, etc.
And this makes about zero sense for Apple people who are so quick to stand in line per "shut up and take my money" for multi-thousand dollar laptops and thousand dollar phones. Countless threads about Apple losing phone marketshare will have counter point (almost proudly asking) "but who has the most profitable phone?". Other threads will gush about "$2XX Billion in the bank". Recently, threads have begun to excitedly anticipate Apple as the first trillion dollar company (like any such corporation is personally good for us individual consumers).
Apple likes it's profits. Fat profits is how it's going to become a trillion dollar company. All stuff sold by Apple is going to get Apple it's profits be that new tech or watchbands. Hunting for something from Apple that is also a monetary "bargain" is almost never going to happen. It's like we believe Apple can launch a Netflix-like service and would do so at Netflix-like prices. No way- even Netflix can't get the newer stuff available from Apple into distribution at Netflix pricing. OR we want Apple to buy Netflix but apparently believe that Apple would then leave Netflix pricing about where it is. No way. Apple likes it's profits. All decisions seem to start with profit margin and/or "thinner" and then work out the rest from there.
Beyond pricing, buying via iTunes means you don't own what you buy. Even Apple doesn't own what they are selling. Ultimately, the Studios can yank their content right out of this "digital locker" and you just lose their part of some virtual video collection "in the cloud." IMO, best option for price and ownership entirely within your control is still buying discs. Convert them yourself and you also control video & audio quality. And you have a tangible backup should your hard drive(s) conk. Discs are often cheaper- especially in the used market where a used digital file suffers no degradation vs. new. And discs can be sold or willed to someone unlike virtual leased files.
The whole trust iTunes, trust "the cloud" mentality is basically letting "the future" spin fool some of us into believing for-profit strangers won't exploit their total control of your virtual media collection at some point.
Personally, I'll agree that media cost is a major factor, along with the thoroughly-walled garden and cost of playback hardware

apple:TV (vs. many competing boxes generally offering more punch for less cost). I'll also offer lack of focus as a culprit- while Apple still seems to be treating it as a hobby, much smaller players with much less cash have focused teams striking deals to make their offerings more attractive. I really like

TV but wish Apple would allocate a ROKU-like or similar team to focus solely on making it ever-more appealing & capable.
Lastly, I'll also offer that the big media companies probably want it this way. They saw how Apple thoroughly dominated their music-industry cousins and don't want to find themselves so beholden to Apple as major distributor. Apple as one distribution partner among many seems to be good for the industry. Apple as the overwhelming dominant distribution partner seems to be good for Apple.