It's a tough one.
There hasn't been much of a baseline for CTE until recently, so while it may SEEM obvious, no one knew the extent of CTE symptoms.
Chute Boxe is a great example: they just thought "train harder and you get tougher".
Train harder and get tougher would appear more common sense than something requiring the foresight of "oh, if I take these hits now, it pays dividends to neurons firing in the future".
I hope they win their lawsuit.
BUT....
I do think fighters should implement training systems like Tim Kennedy or GSP did: they know they're tough, so there was no reason to go hard in training. It was all about technique and getting it right.