BigWheels ARE wicked cool!
Admittedly, they were constructed with suspension components that would have seemed sub-par in the seventies, but that just makes them very easy to improve upon.
Sometimes, like in very muddy conditions, the front wheel will offer too much flotation and not track at all. This leads to crashing while going in a straight line on a level surface. That can be overcome with a little more attention to the surface you are traversing, but is still not the most desirable characteristic.
I think that the fatal flaw for the BWs is that women find them to be repugnant. Orange County Choppers can sell all the big, stupid, worthless, overpriced turds that they want because women want to take off all(or most of) their clothes and get their pictures taken next to them.
BigWheels would be very popular if that was working for them as well.