DS - your comment about UFC is noted "And yet UFC seems to continue to grow."
There are significant moves around the world to stop it. Just like boxing, it appears the medical opinions are being "worked around" rather than addressed.
The point you make however misses the crux of the argument about CTE and its prevention. It is the repeated "minor trauma" not the single incident that is causative.
There is a easily readable explanation
here.
It is based on the Boston Study
here.
Whether it is lawyers who will bring change or politicians (Senate enquiry
here.) remains to be seen.
There is also the counter argument or trying to maintain physical fitness in young people. I do not know how this will play out but I do understand there are many conflicting motives at play.