I don't doubt it. But the clubshop spend on matchdays at the Amex wouldn't be on anything like the scale of the tourists we see at places like Old Trafford and the Emirates, which is why their matchday income is through the stratosphere compared to ours (and the fact their stadiums are more than...
Plus clubs of that ilk have a sizable number of daytrippers, plastics and tourists to their home games, making a rare pilgrimage to the stadium from some far-flung part of the country (or world). Those people spend FORTUNES in the club superstore on matchdays. You see them in their seats...