That's lazy to me, after a 4-13 season. You should be entertaining all options and not some predetermined succession plan.
It's probably not Jerod Mayo's fault they went 4-13.
I'm guessing that there was a lot of thought put into that succession plan, and it wasn't something that Bob or Jonathan came up with on a whim. They've already devoted resources and put time and effort into executing that plan. People have been hired with Mayo's input.
If the defense had fallen apart this year under Mayo's watch, then I think you might have a reason to doubt your sucession plan. But it didn't. Mayo's unit performed at a relatively high level despite being beset with numerous injuries.
To put it in Patriots terms... Jerod Mayo did his job. He didn't give the Krafts a reason to change the plan.