Wayne, again you simply just don't understand how stuff is built. The material costs in building the curved boards correctly is more than a straight board, the time is more also. The internal structure is very hard to build. Consider this: to have a high density stringer inside an F18 board is pretty easy, you just insert a straight spar in the build process. Now how do you do that for the curved f20? You have to make the stringer pre curved and the loads (as you can see from onboard video) are very high. So you need to make the board suitably strong.

keeping that in mind, the price of a F20 Carbon board is not drastically different from a F18 board, especially when you consider that the board is larger as well.