Pro boxing can continue as a profitable spectacle without requiring lots of "developmental" amateur participation. For decades, most boxers have been drawn from relatively disadvantaged populations (recent immigrants, minorities, etc.) who are less likely to have access to the sort of legal representation required to address CTE liability. Who would they sue anyway? Most boxing gyms are dumps that barely keep the lights on.

It's interesting to imagine football going that way. The college game would probably have to disappear. (which it should do anyway because institutions of learning should not concentrate most of their energies on frivolous contests between indentured servants) High school teams might be replaced by AAU teams run by shady coaches who could never be sued. I'm not sure where they would play, however. A football field is a big investment that is always going to be attached to some deep pockets. It's not clear that football could survive in the same way that boxing survives.