You are dead on.
The days of a hand full of teams dominating college baseball is long, long gone. The other schools are putting more emphasis into their baseball programs, not just the programs like MSU, LSU, FSU, Cal State, etc.
I think the last program to dominate the scene for several years in a row was LSU in the 90's till they toned down the bats and balls.
On top of that, MLB is taking MANY more players from college than they did a couple of decades ago. Couple that with scholarship limitations and it is difficult to reload from one year to the next. There are some schools that have the ability to work around the scholarship thing like Vanderbilt.
If the NCAA would give us more scholarships and increase the roster, then we would be closer to just reloading each year.