I suspect Josh would want to stick around Buffalo rebuild or no rebuild (though talk of a rebuild of this team seems silly to me). The Bills believed in him in a HUGE way and continue to, and he seems like a loyal guy. Plus, he has to be treated like a god in the greater Buffalo area.
That being said, if a LA/SD or west coast in general offer came in, he might be real tempted to take it because of his wife and family.