I think that has more to do with the value of true aces skyrocketing to the point that Zack Greinke and David Price were getting over 30 million a year at or around 30 years of age. To avoid those faulty contracts, teams look for quality bullpens at pennies on the dollar and use them more often. If you have aces, they pitch deep into games still. Look at the Astros starting rotation. That has just become a luxury, unless you have aces still in their rookie deals like the Mets. They just couldn't stay healthy.
However, there are no salaries in college baseball. You can recruit as many shut down aces as you can find, but they too are becoming few and far between in the "throw it as hard as you can in case it is a strike era" that are finding ourselves in.