Unfortunately McD will get another season, maybe two, based solely on the perception factor.
But McD lost the locker room this week, and most of the fan base too. This misstep is so huge that I don't see him ever recovering, and I am not trying to be dramatic. Benching a respected leader and QB who has you in a playoff spot for a rookie that comes out with the worst performance EVER (in the merged league) is a fireable offense.