Not at all true — done consulting work for some major media companies, and they vastly preferred people to buy (just think: ~$20 vs. $3.99). I think DRM is just programmed into how the industry views the world, unfortunately.
Hence, the DRM.
If it comes with DRM, it's a rental, not a purchase, no matter how much you paid for it.
Why hasn't there ever been key-transfer features to facilitate sales/trades/loans? Why are there always platform locks and media locks and account locks? Why is there so much effort to stop legal backups, loaning, libraries, etc?
I don't doubt individual good people or divisions exist in major media companies that would just as well sell a movie for $20 and be done with it. But the repeated DRM strategy does not jive with that at all.