CTE is short for chronic traumatic encephalopathy which is a degenerative brain disease. I do think the discovery of CTE has impacted the popularity of football, at least in terms of the number of younger players participating in the sport. Mothers are definitely more worried and even some fathers who once played football no longer want their sons to play. And, this is despite better helmet protection and more rules about contact in youth football leagues.
I don’t think the discovery of CTE has really impacted the popularity of watching football. There are still plenty of college and national football league fans who will binge watch game after game on Saturdays and Sundays