It's like asking why they bother paying customers with anti-piracy ads at the beginning of legally-purchased DVDs when obviously pirates are going to trim them.

It's like asking why they bother paying customers with anti-piracy ads at the beginning of legally-purchased DVDs when obviously pirates are going to trim them. It's not supposed to be reasonable. It's design by committee, it's bikeshedding, it's weird clauses in complex contracts etc... From the right's holder point of view your reasoning doesn't make sense, instead it goes the other way: if people buy our product anyway when we do it that way, why change it? Do you think that when NBC licenses The Office to Netflix they care about Linux users not being able to stream it in 1080p? Do you think Netflix is willing to spend time and money to fight for the tiny portion of the user base who both watches Netflix on Linux and cares for high-def?