they've lost their 'shine' after 10+ years in the B10. Nationally, they aren't seen as a big deal any more. I'm not sure that they can ever get that back in the B10. Plus, where are they going to put their other sports?
The only teams that can really pull off independence (competing financially with p5 money) are: Texas, USC, tOSU, Michigan, Alabama, ND, TA&M, Florida and maybe OU. BYU is pulling it off out of necessity — but not earning the same $ as the p5s.