It definitely needs to be investigated to get a better sample size.
There are 32 teams with 53 players so about 1700 players each year. Assume each team has 53 different players in 10 years so 3400 players every 10 years. if the average age of the brains tested is 50, there would have been about 30 years of players or 4100 people who played in the NFL. Many more who played in college and many many more who played in high school. 111 is a small but sgnificant sample size if they had been selected at random. Only those who showed symptoms were tested. Without knowing how many people in the general population have CTE and without testing more players, it will be difficult to say it they have a higher rate.
If they can prove that NFL players have a higher rate, then they have to determine why. Is it the head trauma or is there something else that players do?
Could it be steroids causing the problems? Are there other things they used?
Certainly stopping hits to the head is justified. Maybe sensors in the helmets to track head trauma.