North Carolina is beautiful, they obviously are paying him, he has been hanging around Washington with his son and friends and seeped in the college atmosphere. I think he likes being a teacher first and foremost.
He didn't even wait for the NFL season to end, all the jobs to come available or the interview process... he clearly doesn't give a rat's ass about "his legacy" because it's already chiseled in granite. When they talk about the greatest pro coach of all time, his name will be one of the first mentioned.