The fact that things are done to protect the players such as lowering the aiming point to avoid head to head have not made the game any less violent. There are still huge hits. Do some refs carry it too far (e.g. Kenny Bells hit) yes. In some ways it is more violent as a result of the size and speed of the players. If you look at games in the 60s and 70s. The average qb was only about 20-30 pounds lighter than the average DL. was less than 100 pounds heavier than the average QB. In the 70s QBs on average were the same height they are now. (6'5") and about 20 ls heavier. So not a huge difference. Whereas DT are the same height but 50 lbs heavier then they were in the 70s. OL has had an even bigger difference. They have gone from 245 in 77 to 320 in the early 2000s.
https://www.pro-football-reference.com/blog/index7255.html?p=493 Both D and OL have continued to get bigger in that time. In that same time 40 yard dash times have decreased. that means bigger guys ae hitting people faster. If you look at how to determine linear force and impact. It is Mass X velocity. So bigger guys hitting at a higher velocity equals a much harder impact. So changing the aiming point only makes sense. IF you care at all about the health of the players. You see hits now that are actually at least as violent if not more so than the 70s. It is just at a different aiming point.
