On paper, his Green Bay teams are not very talented. Particularly at the talent/speed positions (RB, WR, CB) and the interior trenches (particularly IDL). I also don't think Jordan Love would still be a starting quarterback in the NFL on many other teams. So to the extent he gets the most out of the least, he deserves some credit for routinely making the playoffs.
That being said, I also don't think they're winning a Super Bowl with him. It's not all that dissimilar from the Ravens problem. He seems to have hit a ceiling, but it's not clear if that's a talent issue or a coaching issue, and if you fire him he instantly gets a job and probably makes you look stupid when he pulls a Mike Vrabel.