I won’t go so far to say that Garrett is a bad coach because I don’t think he is a bad coach. I would place him in the average category and I think his overall record will substantiate that. I don’t see him as being able to make it to the Championship level and in my opinion you have to be a very good coach with qualified personnel on both sides of the ball to get there. He is as good as some of the coaches in the NFL but that won’t get you over the top.
That's more or less my take -- with the exception being that, average coaches reach Championship games all the time, and Super Bowls not infrequently.
Getting an elite coach is worth way more than getting elite talent, because the coaching impacts everything, and the talent lasts a lot shorter time, so there's no question there. But guys like Brad Childress, Mike Smith, Dan Quinn, Mike Zimmer, John Fox, Doug Marrone, Chuck Pagano, Jim Caldwell, Rex Ryan, Norv Turner.... these guys in the past decade or so have one or multiple championship game appearances. Some have been to or won the Super Bowl. But these guys are also largely journeymen head coaches who are Garrett's effective peers. I mean, unless you want to try to argue that Brad Childress, John Fox or Jim Caldwell are better head coaches, but there's really no measurable that could substantiate that, other than to claim merely making a Championship game means he's better (which I reject, on the premise that there are too many variables to make that simple conclusion).
The ones in the past decade who are clearly better are the ones who get to these Championship games again and again.... Belichick, Reid, Tomlin (though I think that's debatable), John Harbaugh, Sean Payton, maybe Ron Rivera (though he's up and down). Perhaps Sean McVay is going to join that category, maybe Doug Pederson (though frankly, that's a situation that I think is COMPLETELY based on the personnel/front office.... I think Pederson would tank anywhere else).
But then there is also the list of losers who get hired, might be hot names, and then are fired again and completely forgotten. Garrett is better than those guys, and that's a long list.