Mike runs them, because he wants to feel them. This is a big reason why he's running the 18's and they are running extra subs on the side fills on his side of the stage. (or at least on Uproar)
Even in 2010, as micromolder is likely referring to, they were running cabs on stage, they were just placed behind the scrims that made up the backline. Believe it or not, they put a huge amount of thought into how the stage looks. That tour they made the decision to scrim the cabinets.
While the majority of Mike, William and Jerry's sound is all coming from offstage, they do run the cabs onstage and also mic them. You best believe anything they are doing is done right, and has more thought and research put behind it then any weekenders could dream.
Everyone involved in the band and crew is at the top of their games, there are probably a only a handful of people not involved that are qualified.
Some of the interesting things to note is that they are running 6 actively switched (with mix profiles) vocal mics, IEMs, floor wedges, side fills, and live stage cabs. On paper to the average guy like us, it sounds completely ********, in reality, it is working perfectly, and it's not by luck.