10 team leagues are too small and soon become boring for spectators. The game would be better going semi-pro and reverting to one big division in the hope of reinvigorating some of the old rugby league teams by having visits from the bigger clubs.

I've yet to see concrete evidence that rugby or football players get dementia/CTE problems over and above that within the general population, can you point me to the reports?
The case against getting out of bed, walking down stair, getting out the shower, walking, driving is far stronger re head injuries and the damage that does both short and long term at populatio level.
Cycling for example has a slightly lower injury rate than people on foot, it's got worse since helmet wearing was pushed in the mid 00s post UCI then British Cycling enforcing wearing which fed down to every other ignorant do-gooder orgs, the point being that risk is badly understood by people and they base decisions on emotion and ignore other things going on around them in every day life that have same or worse outcomes overall.

When supposed greater protections are brought in, any notional benefit (which is never the same as real life IME) is usually offset by risk compensation (as seen in all helmet wearing activities/sports) and then made worse by inactivity due to participants no longer wanting to participate, so injuries and overall health drops/obesity increases.
So for countries like Australia and NZ, when helmets were introduced with a penalty for not wearing, children expecially gave up in their droves (over 90% of teen girls stopped cycling in one state within months) and injury rates went up as the focus was put more on the vulnerable than the persons doing the harm, NZ and Aus have some of the worst rising obesity rates in the last 30 years.
Same thing in Ice hockey, boxing, pro cycling, American Football, even cricket, all fallen foul of attempting to make the sport safer but the overall outcome was worse regards head injuries and even deaths.

Reported head injuries in England and Wales (to a medical professional) were from the last papers I looked at around 1.6M/yr, not all hospitals gave figures so that's an under report, according to Headway 350,000 admissions in 2016/17 for acquired brain injuries.
If we want to destroy society/make it worse overall then attempting to remove risk completely or some figure that seems to be acceptable to x group of people is the way to do that, all it does is work against public health at population levels and EVERYONE suffers, not just those that have stopped doing the activity.

Ill just quote the last paragraph, but acknowledge a great post, very interesting, and the reaction to the latest head injury worries in rugby & football, i.e. business as usual, seems to show that people are ready to take their chances. Every time I watch the tough contact in rugby and the soccer lads and lasses heading the ball I will appreciate their skills and bravery all the more.......

They get out of the way when you come along just like the WUM's on here

It was a turn of phrase that was a poor attempt at humour, but now you mention the cats, that in itself points to you being a "cat woman" or there being another food source on site