If I were being forced to shift a transmission manually on a trail I would be concerned with "low end grunt", but my sled uses a torque converter that keeps my engine on it's power band, no matter what speed that is.
If I were bragging up a twin, I'd be talking about less maintenance (2 plugs, 2 carbs, etc.), less weight, or fewer moving parts, trying to down play all the advantages of a triple. If I were arguing the triple, we could start with their sound, and go on to trading a case of handlebar vibes or buzz with the large twin for awesome smoothness, better inherent volumetric efficiency (ability to fill the cylinders with a fuel charge) for more horsepower per cc, the insignificant difference in weight, and on and on. But I don't think that's the point
The point is everyone wants to think they are one of the crazies that run out on the MX tracks, or own a machine like those guys are running. They buy a twin because that's what won a race last weekend or last year, not taking the time or caring to consider how many times a day they fly off a 12' jump in everyday life. It's called marketing. Polaris will build whatever sells. Especially when they are cheaper to build. There is nothing wrong with the triples. Yup, there were some problems with some of the triples, but we won't have to go far to discuss problems with twins either.
AL