Rugby and boxing are at essence rough, vicious and dangerous sports, and, while this is not exactly civilised, it is what makes them so popular. These and many martial arts are unlike other sports in that a lot of it involves physical domination which can cause some damage
You either scrap them altogether, or accept that there are risks once you have mitigated the worst of them.
There obviously needs to be protection for kids, who generally do not have the ability to appreciate the dangers involved, but sporting bodies need to ensure that anyone over, say 18, who wants to take up such sports at local league or above level has the potential long-term risks fully explained to them and sign a waiver indemnifying their club/governing body against future claims. Insurance costs may rise as a result of this approach, but those who want to play would have to decide if they were prepared to pay.
On a minor point I think it was
@Tripster who asked if Owen Farrell had reigned in his aggression because of his greater awareness of the effects of head injury. I think he has cut down on the illegal high tackles and shoulder charges because of his recent ban and the realisation refs had sussed him out.