I can understand that. But the NHL is also doing things in line with what you suggest. Head hits are illegal. They could be enforced more rigidly, but they are illegal and we do see suspensions handed out for them.
The NHL doesn't manufacture helmets but their partners like Bauer and CCM do, and are constantly innovating and trying to build a better helmet.
Mouthguards and visors are now common in the NHL but it's actually the NHLPA who fought to not have them be mandatory. Visors are only mandatory for new players, mouthguards are still optional.
I can see why Bettman is denying... he serves the owners. He's not going to say something that is going to cost the league hundreds of millions, if not billions of dollars. He is in a tough spot.
In my opinion, at some point we all have to say "There's a chance you can get horribly injured, and there's a chance your brain could be negatively affected in a way that you could ruin your quality of life down the line. And it's up to you whether to accept that risk or not. But the game's not going anywhere."