A few other points - first, from what I can tell, the third pounder used two 3 ounce patties while the quarter pounder used one 4 ounce patty. So it's possible

A few other points - first, from what I can tell, the third pounder used two 3 ounce patties while the quarter pounder used one 4 ounce patty. So it's possible that it looked like less to people. Second, the third pounder later changed it's name to the Papa Burger. Though there's a lot of discussion claiming the name "third pounder" hurt sales, I can't find any information about how the change in name effected sales. And even after the name change, it still doesn't seem to have been nearly as successful as the quarter pounder or the whopper. Third, the way A&W management talk about this makes it seem like if they just offered up a larger burger a good chunk of the population would come to them instead of McDonald's. It sounds like they convinced themselves that "bigger burger" was going to be a hugely successful campaign, but it's likely a lot of people didn't care that much. I wouldn't be surprised if some people opted for the quarter pounder because they're bad at fractions, but my guess is that there are other, more important factors involved. When choosing a fast food place I doubt the first thing that pops into most people's minds is "how many ounces are in everyone's signature burgers?"