There is one reason that Sumlin to Purdue isn't batshit crazy....the lower expectations at Purdue and the lower ceiling for success in the Big Ten West (and minimal media scrutiny) could mean a job with less b.s. to deal with.....and at some point, that's got to be attractive to a coach who is going to get paid several million dollars per year anywhere he goes.
in the SEC, you're only a few transferring players and losses away from being on the hot seat. Remember, before this season, the big story at TamU was that three stud QBs transferred out within a year. Of course, they will always have more money to pay him more, but if the job can go sour in an instant, it might not be a wise long term play to hang around.