That's very likely to be the case, unless, of course, there's a sudden unforeseen breakthrough in terms of finding a treatment for the condition which is something we really can only hope for at this point.
The worst part about CTE is that, according to some preliminary studies, the degenerative progress in the brain tissue only seems to accelerate even after the brain no longer absorbs any further impacts, and if the impacts just keep on piling up, then well... It doesn't exactly take a career neurologist to presume that it only makes matters even worse.