But there needs to be more, How come Scotland doesn't get a grass court event? Novak Djokovic gets the Djokovic Open in Belgrade, Rafa used to have the Rafa Open in Mallorca, Feds gets the Fed Open in Basel but Andy Murray can't get his own open in Scotland? Cmon!
There's enough rain in London without going even further north. You'd be playing the final on the second Thursday for a regulation 250 event!
In all seriousness though, you have to remember that there simply isn't the facilities for an event like Queen's in Scotland. By the time they start the planning, building and opening of the event Murray would have retired anyway!