I don't think the Patriots are better than the Steelers, it's more that I think the Steelers are smoke and mirrors and Patriots win on Thursday wouldn't surprise me. I think the gap between the two teams closer than 2-10 vs 7-5 looks like on paper. As noted above, the Steelers have been outgained in 10 of 12 games and are 7-1 in one scoree games which usually is unsustainable.
Both offenses aren't very good at moving the ball. The main difference between the two is the Steelers have avoided turning the ball over, they are tied for the fewest giveaways in the NFL this season while the Patriots are 26th. They are now turning to Mitch Trubisky who has historically been a turnover machine. It wouldn't surprise me if it's a punt fest and Mitch turns it over one too many times and the Pats win 12-9 or something stupid.