I think whatever chance there is to bring in a new HC would be improved if clowns like Switzer and Lacewell got in Jerry's ear to tell him how poorly a job Garrett has done this year.
He still confides very much in those two bozos and talks to them every offseason. If they have any sense whatsoever, then they too will have noticed how teams all around the leagues have overcome injuries and poor QB situations to get a few wins here and there, while we immediately went to shit without Romo.
If they point these same things out to Jerry, then it might push him a bit more to make a change.