stronger and more relevant or just concede their death and wait until they blow up (see OU leaving). then P5 will become P4 and make CFP much easier.
or, if they had any pride at all, expand, try to become more relevant and stronger (i.e. don't just add "market" teams add football value) and re-cement their worth as a P5 and push for CFP to become 8 with 5 auto-bids and 3 at-large.
this is a scenario where i think BSU/BYU pair makes the most sense. i'd even try to ship WVU to ACC or B1G and steal Neb back too while i'm at it.