I have always slightly leaned toward the theory that the NFL perpetuates certain franchises to remain in the running for the Super Bowl. Teams like the Patriots, Steelers, Cowboys, Packers usually get the benefit of the doubt...much more so than say....the Browns, Buccaneers, Rams, Titans. Long running successful franchises is good for ratings....and good for NFL $$.....and the Refs know that.
No team can draw a penalty flag against the opponent......resulting in big changes in outcome (3rd, 4th down plays) like the Steelers can (did anyone see their game vs the Jags?)
Another example...Broncos have the ball 2nd and 3 with about five minutes left (with the lead)....and run for the first down. Now they can work the clock down. However....(penalty flag).....the right tackle was slighly out of alignment, resulting in an illegal formation. A call that is not often made even when it is noticed.
So, now it's 2nd and 8. Of course....the Broncos don't get the first down...and have to punt.
Another example. at the end of that Bronco possession, their punter crushes the ball sending the Punt Returner backwards to the 30 yard line, preventing him from having forward momentum resulting in a poor return....and the Steelers get called for holding. Ball would be at the 19 yard line. But have no fear Steeler fans....suddenly there is another flag.....and after about a three minute discussion with the team of refs.....low and behold.....the Broncos get a penatly for illegal procedure (of which I could not see on the replay).....forcing a replay of the down. On this attempt the punter shanks it....and the Steelers get the ball at the 40 yard linfe. A 21 yard differential.
Just about every time the Steelers failed to convert a passing play on 3rd down, Roethlisberger and Tomlin are motioning to the Refs requesting their "on demand" flag.
The NFL needs to learn that it's OK to let Steelers, Packers, and Patriots slip into the abyss. Other teams will rise up and take their place. Only when the propped-up team completely enters futility (see the 49ers) will the NFL refs cut them loose.