If boat race coverage were proportional to the number of contestants, you'd never hear about the America's Cup, but you would read about lots of Laser regattas, Optimist Dinghy regattas, and J24 circuit events, etc etc.
Boat race coverage is proportional to organizer's effort & success in gaining access to mass media. Sometimes this access is directly augmented by money (e.g. hiring professional media or PR firms to promote events), sometimes indirectly (press is trained to "follow the money").