Also, the HP merch is hard to get. That makes it more desirable.
just a thought or so on the comment from the article regarding fans waiting in line to get into WWoHP shops..
My wife and i were in WDW for our honeymoon 2 weeks ago and after a week at WDW we visited WWHP (we pretty much loathe visiting universal but figured we would regret not going to see it.. and both like the movies a lot).. as far as the lines to get into merch shops are concerned, they are not simply because everyone is dying to throw money into them but largely for 2 reasons, 1) they are sort of part of the attraction, since they are supposed to be shops from the story lines, which of course everyone is aware of, so a lot of people want to see everything there, but also 2) they are WILDLY small.. not just small but like fire-hazardous, unbelievably cramped small.. so only a very small amount of people at a time can go into them. After waiting 45 min (literally) to get into Dervish and Banges we were very disappointed at both how small it is and how few things there were that weren't to be found in other shops (you basically walk in a cramped single file line to get through a place the size of an apartment). Other than wands in Olivanders (which had an hour long wait) and some quidditch stuff in the castle shop there wasn't much that couldn't be found elsewhere (other than the candy and such, of course). We loved the ride but certainly don't plan on revisiting every time we go to Orlando for WDW.. And I tend to think the success of the merch they do have is because so much of it is stuff that is like directly FROM the movie (we got Dolores Umbridge rule decree refrigerator magnets,)..
Basically all WDW needs to do is build the damn Beastly Kingdom with a crazy robocoaster ride.