That's basically it. Also, PTV's are a pain in the rear end when it comes to maintenence. To fix a PTV (and there is usually one broken one on every
flight, you need to rip out the entire seat. Not exactly pleasant, plus it keeps the aircraft out of service more often than it should need to.
That would be the reason why every airline in the world hasn't suddenly jumped on the PTV bandwagon. Maintenence issues made it cost-prohibitive for many airlines to offer it. Finnair just did a D-check on it's first MD-11 (the first D-check carried out on an MD-11 ever) and they put in new Y-class seats with those winged headrests and improved entertainment controls, but no PTV's.
Personally, I don't mind. I spend more time looking out the windows anyways. That's MY PTV
Head in the clouds... yet feet planted firmly on the ground.