The reason they are so expensive is because of manufacturing costs and exchange rates. While many companies choose to subsidize the cost of kits to increase popularity Kyosho relies more on reputation and team drivers like King and Tebo instead of discounts. Its really similar to BMW vs Honda in 1:1 cars... BMW doesn't discount cars (not in subsidization any ways), the price is the price and you are going to pay import fees if you don't like it go buy a Honda. Honda on the other hand subsidizes the cost of their cars so no-one else up until recently gave you more car for your money. You want a full sized car with heated leather seats and a 6CD changer and premium speakers? An Accord with all that will set you back ~$30k whereas the same BMW will cost ~$40-60k.
Honestly it must have something to do with the very american way of thinking that if it costs more it must be better right? :P
That said my opinion on K is that they sure drive nice but when they break its usually a what the hell happened out there... Snapping drive lines and exploding spur gears come to mind recently...