The subject of this thread is really quite interesting. From my perspective, one of the most notable take on the production windsurfing industry today is that it has actually taken on the character and flux of the "custom" side of the spectrum.
In the old days when boards were produced from expensive molds, the opportunity for change was heavily restricted because a company was obligated to hang tough to cover relatively large up front costs for design and manufacture of tooling. To reap the thrust of progressive design changes at that time, folks really needed to focus on the custom side of the industry. In addition to realizing the latest designs, the custom builders also provided the opportunity to get into some wild and striking graphic statements too.
Now that the production side of the industry has matured in the direction using methods more like "custom" manufacturers, the opportunities to change and evolve designs, to include flamboyant graphics, has reached a dizzyingly level. Really, with respect to graphics, the production industry has reached a level that arguably exceeds that of the custom industry, since complex custom graphics are so time intensive and costly to produce.
However, with all the benefits of virtual "custom" manufacturing, the production industry has created an almost fashion approach to style and design, such that last year's trends are seemingly outmoded next to the current new releases. When you stop and consider it, the actual worth of last year's designs is significantly less, even if the product is brand new. Of course, that's great for some that can rationalize investing in an "old" design (I have to smile a bit when I say that).
Much of this fast pace fashion thing is artificial and simply marketing induced, it's interesting to stand back and think a bit more about the viewpoints highlighted by marksw and geo here. Maybe a slower more deliberate pace of things makes sense from both the customer's and the industry's perspective. Rapid change has its cost. Frankly, I think much of the cost of fashion and changing designs might be better invested in construction innovations that influence longer product life.