I'm not sure about Negril, but to my knowledge, there are no megastores in Mo Bay or Ocho Rios. (At least I didnt see any) Lol, when we were riding towards Ocho Rios, the tour guide said, 'Coming up to your left you will see Walmart'. We were all anxiously waiting to see it! It was a local's hut, with Walmart written on the sign outside! lol
I think building a megastore in Jamaica would put a lot of the locals out of business. As Jamaica is a very poor country,and most of their revenue is generated from tourism, but I dont think a lot of the locals would be able to afford to shop there very often! I think it would hurt their economy more than help. just my opinion