Legally, if they own the system/game they should be allowed to rent/sell/stream it to whoever they want.
So why don't they?
Mario Kart 8, Smash, NSMBU, BoTW could be available to all gamers if Sony/MS bought a few WiiUs.
Nov 2016 - NES outsells PS1 (JP)
Don't Play Stationary 4 ever. Switch!