Netflix doesn't stream at blu-ray quality at the moment. I think for a lot of people the appeal of HDTV was a bigger screen. I know people who have HD and still watch SD channels stretched because they don't even realize it. And google "3D is dead".
Shooting in 4K might not be a bad idea depending on the costs but I'm not sure the public will be banging down the doors for these just yet. I don't see any harm in reasonable future-proofing but I don't know that they need to go too far. Ironically, the best future-proofing might be to shoot on film with practical effects.
There might be more than tech though, BBC America is showing nine(!) reruns of TNG today, why not the later series with HD and newer FX?