If Belichick had already passed Shula by now, I think he's retired and just chilling in Nantucket.
And even as I hear his answers to questions in his morning interviews today, he really doesn't sound like someone who cares right now, or at least not someone who is willing to go above and beyond to fix the team. He's just giving "corporate" answers and stating the obvious ("yeah we need to get better", "we need to start over", etc.). He probably doesn't believe in the team or the QBs, which is ironic because he's the GM who literally built this roster
I agree with others, Belichick has done a lot for this team and is the GOAT of coaches, so you won't fire him mid-season. But there's no excuse not to fire him after this season if they finish with less than 7 wins and it continues to look bad. I also wouldn't want Belichick picking high in the upcoming Draft either, for all we know he'd just trade back or pick some insane reach.
The alternate is Kraft removing GM duties and other power from Belichick outside of coaching, but I doubt Belichick agrees to that and he'll probably leave, so it becomes a "mutual parting" maybe with Steve Belichick also gone and Mayo promoted officially. That seems the more ideal route for all parties. Belichick can pursue Shula's record on a team like the Chargers who should immediately dump Staley if Belichick is available.