You only need to do the math yourself to figure it out. At the D1 level you can only carry 35 players. Go to any D1 programs website and look up the stats. How many position players are getting the at bats? How many pitchers are getting the innings? How many of the players on the rosters are Jr's and Sr's? When you look at the elite programs the numbers are even more telling.
Now think about the level's of play where there Is not a 35 man roster limit. The opportunities are the same but the numbers are higher. MOST kids do not go to their school of choice, stay four years, play a bunch, have a great experience and then graduate. When I see a parent post on this site that their kid "Finished" I am so happy for them. That is a tremendous accomplishment. I don't care how they did it. If they played at 3 schools. Saw some spot duty. Had a good year. Was a back up his entire time in college. I don't care. If he finished and got a degree he has accomplished what most will never accomplish.