well sure, if skill levels are equal strength is key.
but i would put my money on the average MMA fighter against the average Powerlifter any day.
You don't have to be an MMA fighter to be capable of beating someone's ass. I'll talk specifically about powerlifters since that's what we're talking about, but this applies to all people. MJR, the highest raw total powerlifter we have here (I think, that I know of at least) has never done any MMA or submission grappling or muay thai or boxing or any other striking discipline in his life. He did wrestle in his high school, but I don't think all four years. Regardless, I'd take him in a fight against a BUNCH of heavyweights I've trained with, including Seth Petruzelli and Gabriel Gonzaga, both of whom could surely win by submission IF, and that's a big IF, they could get him into a bad position. I'm no slouch AT ALL on the ground, and I've rolled with MJR. As a pure wrestler, with his ridiculously compact and explosive strength from powerlifting (and being part caveman/part gorilla), he's a scary opponent at any weight class.
Crazy strength absolutely overcomes shortfalls in technique. I've seen really fresh white belts roll for 10 minutes with really sneaky black belts (no gi, this doesn't happen in a gi) and never get submitted. They may be constantly defending, but in a fight, they would be the one doing damage in between submission attempts. We had a former NFL linebacker (Raiders practice squad) come into a Gracie school I had just started at. He was about 30yr old, 6'2" 240ish and as solid as they come. He had no neck......no neck. He rode everybody in that class like it was his job. It was like trying to drop a cat in a 5 gallon bucket of cold water to get that guy on his back. Nobody could do it. Not even two of the black belt instructers. The guillotine was impossible. His posture and lat spread and neck/chest/shoulder size/strength were too much for any triangle. He knew to stack you everytime you locked up an armbar, and he was good at it....painfully good. So good you couldn't even squirm face down and lengthen out. We didn't do any heel hooks or leg locks in the beginner classes, so the guy was basically untouchable. He never got submitted the whole class. So at the end of the class, they call over Marcio Simas, a 5th or 6th degree black belt under Carlos Gracie Jr., and he in turn calls over this Brazilian guy who spoke no English. He was a blackbelt and he looked solid, although certainly 30-40lbs lighter than the ex-linebacker. They rolled, and for 10 minutes these guys gave it everything. The footballer would muscle his way into a good position and just squeeze whatever he had in his arms, lol. It was f'ing hilarious and awesome to watch. He got put in every submission you can think of and he didn't tap once. Of course, Marcio was telling him what to do from about 5 feet away the whole time, but it was still badass.
Point is. Any statement made for either side that uses absolutes is silly. Things happen in fighting. I've rolled with the same chump a million times and submitted him at will, and every so often he catches me. I caught blackbelts every so often when I was a blue belt. Anderson Silva got knocked out hard by a decent striker, but not even close to his level. You just gotta bet on the guy that stands the best chance, and that's not always going to be the more technical guy.