Yes, but if anybody does say that he needs a great defense, it's considered a criticism, meaning he's not good enough to win a SB for the Dallas Cowboys unless he has that, whereas if the Cowboys had another quarterback, e.g. Dalton taking over, it would happen.
Russell Wilson is widely considered one of, and by many, the best NFL quarterbacks. An "elite" quarterback, one who can "carry the team on his back" and "make everyone around him better".
Yet the two years he "led" his team to the Super Bowl, Seattle had the number one overall defense. Without that, he's not been back to the Super Bowl.
So to pose a question, does the "elite" quarterback, one that can win SBs without a great defense, really exist? The last SB P. Manning won, he had an poor, comparatively speaking, regular and playoff season. But he still "won" the SB. How, if he wasn't a "great" quarterback at the time.
The number one, and by definition therefore, great defense was undoubtedly a massive part of that season.
Of course it's not that simple, the Saints deserved to be in the SB a couple more times, based on their regular season, but one poor defensive play and one poor officiating call ruined those seasons' opportunity. Having the great offense/defense was negated by those two plays, both were very late game plays, normally one play doesn't define a game, but if the plays are the last one of the game, or close enough to it, they do. Patriots were extremely lucky to win their last SB, again a very late game play, the absolutely imbecilic play call probably (but you never know, maybe Beast mode would have fumbled, etc.) cost them a second SB win. Aaron Rodgers is "elite", by nearly all accounts, but he's only been to one SB.
Just saying that to concentrate on having the great defense or offense, and achieving that, doesn't guarantee championships. Can't place the blame on Dak, or the defense, or the coaching entirely, but they all play a part in winning or losing.