Pat,
My first round of golf was at Medinah, pre any restorations a long time ago. I truly recall several narrow chutes of trees off the tees. So, it happened sometimes with the older courses.
I believe tees have generally always been under thought. RTJ was evolutionary, not revolutionary with those long tees, realizing that more length on the back tees required many more shorter tees to truly accommodate average length tee shots.
Perhaps it was other architects who set those long tees on angles to vary lines of play, thought to put multiple tees instead of a strip (based on how they played the hole and trying to be different than RTJ( and much later Fazio, with substantial grading, put tees at various angles, hiding each from the tee behind with subtle mounding and ridges.
Somehow, I doubt that is the final step in the evolution of tees, but I think they are improved from where they were in the RTJ era. I recall visiting RTJ II office on a golf vacation in 1980. My mentors used rounded and free form tees (those stolen from Larry Packard and Innisbrook) and we discussed tees. They felt strongly that a tee ought to be a rectangle, and might, maybe, would do one rounded, split or angled tee per course if a specimen tree dictated it. Otherwise, it was a long rectangle. Not sure how related that is, but it is just one of my designers memories!