Have a look at Rugby Union (or Thugby Union as some call it) as well as Rigby league in Australia. No helmets, equally as explosive collisons in tackles, yet no discernible suicide track & players retire & live long lives. Why does it only happen to US players ? Touch overdone ?
How do you know it doesn't? Where do you get your rugby suicide news? I know it's not scrolling at the bottom of CNN where I live -- nor is the NFL. Aside from this movie, where do you hear about it? It's not like ESPN is talking about it cause, you know, they have an agenda.
The helmets and shoulder pads actually allow NFL players hit each other even harder. You can hit someone much harder without the immediate concern about hitting each other so hard.
The tackles in rugby you don't have guys coming in on a 10 foot or longer line at the ball carriers basically exploding through them. In rugby the action for the most part is a lot more compact so you can't get as big of a dead run at someone.
Rugby [both Union and League] can be dangerous with concussions a risk and I wouldn't be surprised if there was some CTE.
However, the rules for tackling are strict and enforced. Players can be sent off for 10 minutes [yellow card] and for the whole match [red card] if repeat offences. Any tackling that doesn't use the arms or any head butting are yellow or red cards.
A massive rule revision and culture shift is needed in American Football or CTE will reach epidemic proportions.
Removing the padding is probably too big a step but stricter rules for blocking and tackling - requiring players to bind on before pushing in a block and tackling like in Rugby would help a LOT.
Of course it would also kill the spectacle. People watch to see the violence. No spectacle, no viewers, no ad revenue and no NFL.
It's a BORING sport anyway, why do you think only the US and Canada play. Better it died out IMO.