A couple thoughts:
DL wants good recruiters. His goal will never be to rehabilitate coaches, but to win championships. No matter what their upside, DL would never hire a Chip Kelly because he doesn't want to recruit.
Rather than be a rehabilitator, DL wants to get young coaches with a lot of drive and good ideas... and help THEM succeed. This has been DL's MO from the beginning. He will hire an old experienced guy to help mentor the young buck (A'lique Terry), but he's not hiring the old guy to be The guy.
Looking back some day, DL's coaching tree will show a multitude of great coaches that started as young, near unknowns.
Some of those young bucks will not want to move on. They will like working with DL. They will like Oregon. They will like the rings. They will realize that the grass is pretty green in Oregon. There may be a lot more coaching stability in Oregon than anyone would imagine now. Dan Lanning has made it clear that he wants to stay.