I imagine that's true, and it's part of the reason I don't assume he'd be a great wrestling coach for submission grappling. Because he started learning to wrestle in earnest after he was already a very skilled MMA fighter, I suspect he focused his efforts on what he knew would translate well to the cage. I can tell you from personal experience that what translates well to the cage is very different from what translates well to submission grappling. You take something really basic like a snap down: super useful move for sub grappling, guys use lower wrestling stances, and it sets up the guillotine/front headlock series. For MMA? Not useful at all because guys are never that bent over. Snapping down someone in MMA basically isn't going to happen. Another example would be something like working from an over/under clinch. Really important in MMA, that sort of upright Greco style clinch happens all the time (again, because of the stances and the fact that you're closing distance after striking). When was the last time you saw anyone working that sort of clinch in submission grappling? The format just doesn't lend itself well to that sort of engagement. I suspect the wrestling skill set Demian Maia has is not well aligned with what you'd want for sub grappling, that's all.