It's because Rockstar doesn't give a fuck. Manhunt doesn't work without a cracked exe on Steam, Bully crashes every two seconds because of Win10, GTAIV is a mess riddled with DRM and bugs related to Win10 too, and the same applies to LA Noire.
The rule is: do you want to sell your games? Patch them. Patch them to be playable in the latest OS. I don't need achievements or stuff like that, just a working game. I bought the GTA pack back in days and still I can't register my cd-keys because of several errors.
Rockstar is really crap, because they do a lot of money and they have resources to do a simple fixing patch, but simply they don't care.