Apart from the fact it's the equivalent distance from Bedford of having a Potter Studio tour in Paris, France . Not 45 mins down the M1 motorway. So the reason would be why would WB be cannibalising business from something they get 100% of the profits from? They're not gonna be interested in licensing
And to answer
@GAcoaster point. Hogsmeade wouldn't be built because they have it in Orlando. So what exactly gets built that's worth paying the fees and has as much draw as the Orlando locations?