Some guys are really advanced and beat up on minor league pitching or they have outstanding tools with a huge flaw that minor league pitchers don't know how to exploit. When they reach the majors, they stop being more advanced or the pitchers know how to use those flaws against them and carve them up. I think Nick Senzel is an example of a guy who was more advanced in the minor leagues, but when he reached the majors he no longer was.
Fangraphs seems to have bucketed pretty much all the Reds prospects in one of those groups. For this rebuild to go anywhere. De La Cruz, Marte and CES have to become guys who can produce in the middle (spots 2 through 5) of a big league line-up.