This was not a condemnation of the Cowboys offense. Far from it. As we all know, Sunday's game may be the first time we see all starters on the offensive line for a very long time. This team had as many as three O-line starters out. That was challenging enough, but then to have two of them replaced by undrafted rookies. I'm pretty certain that some plays had to be taken out.
The repercussions due to injuries don't completely go away yet. These guys have to learn to play together and build the cohesion that will make them efficient and that may take a few games.
There was also the loss of Brandin Cooks and that might have really effected the scoring although I think Tolbert did an admirable job filling in.
These issues seriously effect the ability to score so the team we see on Sunday isn't the same team responsible for their previous performances. It's also true that the same can probably be said for half the teams in the league. NFL teams have a way of 'evolving" during the first half of the season. Ideally, you would want the most efficient version of your team in December and January.
So we should never take statistics too seriously as a measurement of the team we have. They are simply a tool to "approximate" where the team might be.
This may be a matter of semantics but, statistics, if measured accurately, is not flawed. It is the way they might be interpreted by human beings that can be very flawed. The data size must be very impressive for statistics to accurately predict an outcome, preferably in the hundred thousands. Even then the statement will offer a probability and neither the statement or the probability will be definitive.
An example of statistical statement might be. "There is a 90% probability that the Cowboys will score between 17 to 27 points on Sunday". I just made this up as an example so don't quote it...please!
However, as you can see, it's never very committal, not absolute confirmation. Pardon me if you are an attorney but you may have noticed that attorneys tend to do the same, it's never yes, no, absolutely, every time, etc. It's always perhaps, most likely, in all probability. They realize that there are always possibilities that could not be accounted for.
So again, stats can be relevant as long as we understand that you won't get definitive answers but you will get a pretty good feeling about what they might indicate. They might confirm some of what you think you see, some tendency.
Being ranked #1 doesn't mean you are truly the best defense, whatever that means. I say that because each player and, therefore, each team will be a different version of itself every game they play.