I once attended an event where a NG editor spoke. She said that for the average article the photographer takes 50,000 pictures (that was 10 or 15 years ago and it was still film) She also described some of the “expenses” including armed guards and robotic cameras destroyed by animals. Maybe the thrill is more important than the $500.
50,000 images. If you used 36 exposure rolls of film, that is over 1,300 rolls of film. That really seems excessive. Maybe 5,000 exposures?