From William Langwiesche's article in Vanity Fair:
The problem is that there are too many surfers in the world and too few good waves to ride. This may come as a surprise, given the extent of global coastlines, but most surf is unrideable or uninteresting, and good locations are small. The North Shore, for instance, is only 13 miles long. It contains several dozen renowned surfing spots—particularly the “inside breaks” of Pipeline, Sunset Beach, and Waimea Bay, one after the other, close to the shore—but their takeoff zones are typically just a few yards wide, and they are crowded with surfers vying for advantage. Bradshaw calls this the dark side of surfing. The crowding is compounded by the fact that, even on good days at good breaks, good waves are relatively infrequent, and when one finally arrives, even if it is large, it usually offers enough space for just one good run. What goes on as a consequence Bradshaw calls natural selection. Actually, he calls it Darwinism, and means the same thing. It’s not about survival so much as getting the rides. In the minds of people like Bradshaw, the two are related. If you leave a challenge unanswered, the punks will start stealing your waves. There are a lot of punks in surfing. Bradshaw said, “Yeah. I’m not afraid to go for it. I’m not afraid to be underwater for a long time. And I guarantee you I have stood on people.” By people he meant men. For some reason this never comes up with women.