I don't give a shit about what happened in the past. I care about what is happening right now. And Dallas is 5-2 in their last 7.
At the end of November in 2011 you could have said "I only care about what is happening right now and the Cowboys have won 4 in a row and 5 of the last 6". Then they went on to go 1–4 in Dec/Jan.
In 2012 after that big Pittsburgh win you could have said "I only care about what is happening right now and the Cowboys have won 3 in a row and 5 of the last 6". Then they lose both of their final two games to come up short again.
I get it that "it's a different season, you can't expect the same results". That's true if you want to look at it that way but you can also say, hey, this has been a trend with this group (2008 was much the same way). This is a huge "prove it" situation in December and most times the Cowboys have proven that they can't get it done.
Are we forgetting that this is a historically bad defense? It was that way before Lee went down so I don't see him as the savior. The teams left on the schedule are certainly beatable but I'm sure every one of those teams looks at the Cowboys and how their season has gone and says the same thing about them. Assuming that this team can go, say 3–1, and close out the season on top of the division is a big leap of faith, IMO.