Each city has different rules and regulations about taking portraits commercially at California beaches. Of course we know that low end photographers are looking to save a buck so they head to beaches with few or no fees and restrictions.
Most beach sports photographers don't make a full time living in the trade, but they do have fun. Some of the best surf photographers, for instance, are surfers, themselves.
Everyone can take sunsets. Stock agencies have far too many. People pictures for editorial and advertising are in demand. If you can see a face, get a photo release!