The margin of victory is just a measure of how much better you played that day than the other team, or potentially how much better your team is.
We just came from a SB, so of course we would be a much better team than the Bears (who are so horrible they are fire sale offing half their team now, apparently trying to be the 76ers of the NFL). So beating the Bears is sort of like a heavy weight boxer beating a tomato can, it proves nothing.
The issue some people do have, is that even against an opponent that was completely overmatched, an offense that could not score and a defense that (until the end when it was exhausted) was getting no breaks, we could not score TDs. Not only that, we couldn't even keep a sackless team of our QB. In fact, we let them sack our QB 4x.
That said, we are not terrible. The GB team that looked all world last night, we played punch for punch until the end there - that was a winnable game that might have come down to a few bad bounces and one Bevell away from a win.
But this offense has been sputtering, clearly without a healthy Lynch we cannot consistently keep drives going.
So there is the apprehension, but it might just be a matter of resetting expectations. From being one of the best teams in the NFL, we are probably closer to one of the better teams. But we are not far off, we just lost a lot of defensive depth, our OL is a ?, and for whatever reason our QB play is not consistent (and this feels like it might be related to how he is being used, because I think he shines in RO or play action, but when that threat is gone the effectiveness goes way down).