Belichick also doesn't have the highest season winning % of the Super Bowl era even when Brady was here. That's Madden's record.
For me I think the most compelling argument against Bill as GOAT coach is his coaching tree. An all time great coach ought to elevate his staff and make them better. Just about all of Bill's staff over the years have faceplanted away from BB most recently Josh McDaniels.
This is Andy Reid's tree:
Andy Reid's coaching tree: Sean McDermott, John Harbaugh lead list of NFL success stories
www.sportingnews.com
Compare that to Bill's. I think we all know his coaching tree ain't pretty....