"So the magic comes from the interaction of the surfer and the board."
I'm pretty happy to use this definition, where the magic happens. I like it a lot.
However, I think you make a good point regarding pro's and the sheer volume of customs they'll go through in just a year, which I think waikikikichan also mentioned. Seems they'd be more inclined to notice when that one board, for whatever reason, worked better than the others vs. the rest of us. Marketing/branding is also something I should have considered more. Companies intentionally conflated "magic board" with "board that lets you catch more waves and turn," HS Hypto and grovellers come to mind over the past decade. I think waikikikichan was also getting at that in past posts.