I was asked this question the other day and thought I’d share my findings.
The main reason I could determine comes down to economies of scale, although exact (or even nearly exact) figures are difficult to come by, it’s pretty obvious to me that there are a LOT more snowboarders in the world than kitesurfers. As a result there will be a lot more snow boards manufactured every year than kite boards, this drives down production costs and allows them to be priced lower.
Add to this the fact that kite boards have fins (which can be bloomin expensive) foot pads, foot straps and a handle (unless your cool and have taken the handle off!). All these accessories cost money and so it is probably fairer to compare like for like price between a snowboard with bindings and a kite board, when you do this the difference isn’t so huge.
When you actually compare the prices of high end snowboards against high end kitesurf boards you notice much less of a difference, top end production boards in both sports tend to retail for around 600 € the main price difference tends to appear at the bottom end of the price range where you can pick up a pretty decent snowboard for around 200 €. I would imagine this is due to there being a much wider variety of manufacturers all competing for the mass market of people who want to own their own snowboard but only snowboard once or twice a year so aren’t going to pay top dollar for one…which lets face is the category that most of us fall into. The kitesurfing market simply isn’t large enough to support this many manufacturers and so competition on price at the entry level is less fierce.