During Chip Kelly's time at Oregon he capatilized off a down conference and sold extremely nice facilities and 1,000 uniform combinations. Since he has left, the rest of the Pac-12 as woken up and become good, every school has 1,000 uniform combinations, and with all the $$$ going into programs everyone has amazing facilities.
So that leaves Oregon with selling Eugene, Oregon to recruits from So Cal, Texas and Florida. A very tough task to do for a head coach. Also the new coach is still going to have the expectations of what Chip Kelly did there (again much tougher to do now) and you have a mega billionaire in Phil Knight looking over your shoulder and has more power then the AD in Eugene. That is a ton of pressure for a coach, especially a new coach.
It'll be interesting to see what Oregon does here in their hire moving forward. They have since the 70s? hired from within and kept assistants around for a long, long, long time. If they clean house you are looking at a Solich/Callahan type transition. Complete culture change, that some of the current players may not fit into, and add that Oregon is losing out on critical recruiting time without a coach and this upcoming class may be bad.
IMO, I think Oregon should have kept Helfrich for one more season. It'll be interesting to see if Oregon trends downward and stays a 7,8 win type program like they have before this rise, or if they do indeed get back into the elite status. I just find it difficult to do so given they dont have that special edge anymore.