If you live in the past, you will be passed. If these players played today, they would have made so much money they would have trained in the offseason rather than work. While their height wouldn't change, they would be much bigger/thicker.
The typical player doesn't become one of the stars you mentioned in any era. The typical player is average. The average player today is far more athletic and physically developed than yesterday's players. I'm not sure the average players of yesterday could compete in this era.