Actually, Garrett had a radio interview, and said he didn't expect any changes.
In his presser early that same afternoon, he walked that back, saying that his meeting with the Joneses (and presumably Will McClay) was taking place later that afternoon, and that's when those conversations would be had.
Jerry, meanwhile, had said that you never know who might become available in the next couple of weeks.
Garrett, Jerry and Stephen all have said that they make decisions by consensus. It's not hard to believe that, especially in recent years since Jerry's evidently been out-voted on occasion, most notably the decision to draft an OG out of Notre Dame instead of a QB out of TAMU.
Having said that.... Campbell has himself been interviewed multiple times for HC jobs already this off-season. It is altogether plausible that Campbell could get consideration if Garrett falls on his face next season. But don't blow any more bubbles... Jason's seat in the situation room is more like a throne. It would take epic failure, imo, for him to be forced out.