I would guess that his point was that training programs are getting much more intense. With the ncreased intensity there are a couple of possibilities. First, the athlete, being bigger-faster-stronger, may start to exceed the structural systems - muscles adapt much faster than connective tissues and bone mass.
Which leads to point number two: at what point does training cross the line in either intensity or duration to become overtraining? That might well be worth the study.
And I can give you the answer on the folks too dumb to get out of the rain. They don't get much wetter - but they do go to Carolina.