Patchan is a known commodity.
He gives you solid, if unspectacular, reps.
We have absolutely no idea what the young guys bring.
The best way to find what the young guys give you, is to get them the reps.
They can't get those reps because there's a 6th year Senior playing ahead of them...
Then they get frustrated because they're not playing ahead of someone they know they're better than, then they decide to hit the portal after standing on the sideline all year, which kills our depth for the future.
Patchan had multiple boneheaded penalties in games & was routinely driven out of plays due to his poor pass rushing skills. He's been here for long enough for people to realize that the best we've seen of him has already passed, he hit his ceiling already.
The younger guys still have time to develop & grow & get better, they need an opportunity to play in order to show it on the field. It's the reason why Rousseau had 15 sacks as a REDSHIRT Freshman, because he finally got a chance to play & show his development on the field.
Imagine if he were standing on the sideline all season behind an average DE that's not going to get any better, it would be a waste of time & would ultimately hurt us on the field because the better player with more talent & upside isn't playing.