Given the severe decline in the quality of diving, the massive increase in cruise ship traffic/congestion/pollution, and massive hurricane impact reef damage in recent years, it's hard to believe it's divers flocking 'en masse' to Bonaire and running up the airfares. On other travel threads I've heard the theory that recent severe weather events (like the very destructive multiple Carribean hurricanes of 2017) knocked out many of the usual tropical vacation spots, so tourists are re-routing to the places that were spared those damages, which may be running up the travel demand to places like Bonaire.