Bill Belichick Will Likely Never Coach Again
Honestly, I think Belichek's primary motivation for coaching again was simply to claim the all-time wins record, which would've essentially required two full seasons (or one really, really good one) for him to obtain. He would be 74ish by then, which seems hard to imagine anyone feeling confident in him coaching beyond that point anyway and forces them into another coaching search.
Add on to that his mediocre (at best) track record outside of any Tom Brady-led team and it's easy to see why no one outside of Arthur Blank even gave him a look.
Hell, as a Saints fan, I'm disappointed the Falcons didn't hire him. There's enough evidence in recent years to show that today's game has passed ole Bill by.