Players are far more brittle than they use to be.
The ability to stay on the field or never miss a start is now a high value. Then there are guys like Judge and Trout who will still get higher contracts despite never playing a full season. Look at the Gio contract, Did he ever really miss a start?
As for the pitch clock the aging pitchers were having trouble. I doubt any of those legendary pitchers would have an issue with a pitch clock. It works both ways. He hitter isn't allowed to take their sweet time.