I think they have made them so comfy on the head, they have created a TOTAL false sense of security. Oh yeah! They pad out trauma to the head. But NOTHING changes the fact that when the head stops suddenly, the brain keeps going till it bounces in the skull. The fact that helmets hurt less on the OUTSIDE, players are much more comfortable with hitting their heads, even unintentional. Remember old school helmets?? Those damned things would snap your nose in an instant. Side hits did not feel so great on the ears. I also think reducing the face masks with 238 bars would help too.
Tackling is a whole other story. Damned near EVERY player in football has forgotten how to wrap and bring down. They all go for broke with a forearm and shoulder....But guess what is right there too. Their heads!
Even Vince Lombardi said shortly before he passed....Let them break a few beaks and you'll see less use of the head.