Because realized or not, at least there is a chance an upside guy will get better.
A maxed out prospect is what he is, and you really don't know if that maxed out talent is enough in the NFL from college. An example: Alabama. A lot of these guys come in maxed out, never improve and are so-so NFL players. Saban gets every last drop of talent out of them and there is no upside. Now there are plenty of good to really good Alabama football players in the NFL, but there are a ton of busts. Esp the Qbs that come from there.
Now that said Rock, If I am a GM/coach that just traded years of picks to get my QB, I am not sure I can squeeze the trigger on a kid with 19 career starts at FCS. Regardless of how great that FCS team is, or how many QBs they have sent to the NFL.
As a fan of the Rams, I want the 9ers to take Jones, because he is low ceiling, high floor. Trey Lance is low floor, but a very high ceiling and still a moldable piece of clay that if Shanny is the QB whisperer everyone thinks he is (I don't think he is) will turn Lance into an absolute monster.
Don't waste your time looking back, you're not going that way. - Ragnar Lothbrok