If you’re an older player NFL teams are likely going to be able to get fewer years out of you, since most players retire before 28-29. This is how ratings work for all athletic recruiting, across all professional sports. Things like measureables and age are just as significant to recruiting as your college production; that’s why the nfl combine is still a thing. I don’t love it but that’s how it works.
As Jeff Hansen notes, our transfer class compares reasonably closely to most of the other playoff-caliber teams. Most teams who are active in the portal are teams like Texas Tech, with rich donors but not a lot of team continuity.