Bellicheck was and remains known as a stone faced, joyless, pragmatic to a fault, HC. Gets rid of some players that seem on their way to stardom because he doesn't want to pay them.

I don't hear about some huge man-love for Bellicheck, but rather undying admiration and respect.
Players and coaches come and go for Bellicheck.

Not saying McVay is the smiley face version of Bellicheck. Just saying that moving on from coaches and players after a sub par season doesn't mean that the HC is wearing out his welcome. In fact what it might mean is that certain coaches and players have worn out THEIR welcome.