First of all they kind of already are - through escrow.
As you know a certain % of salaries are held back in escrow. The more the league grows revenues the mroe of the escrow is given back to the players. I believe if league HRR is big enough the league will even pay players a bonus on top of their salaries in order to guarantee the 50/50 HRR split.
Secondly though - I think most players just want to put their heads down and play hockey. Even if you're the biggest star in the world like McDavid - you can do all the media, all the endorsements - and it really is going to make a very small difference to your individual take-home pay. If you're a third line winger on a bubble team - nothing you do is going to make a difference to league HRR.