We don't ever need to fire rapidly. The ground is almost always stationary.
The airplane is moving but it is several seconds before it has moved far enough for for the view to change enough to matter. We don't use this camera in a mapping mode, nadir or straight down is when it matters to have fast firing. The mapping camera we have is hooked to a laptop and the laptop stores the images via USB. There is a flight plan software running and it knows via the GPS and IMU where the camera is, and just when to fire. If we are in a C210 or something going 160 and down at 2,000 feet the camera has a tough time keeping up.
The current state of the art dream systems that we will never have cost over a million bucks and have all the bells and whistles. Our mapping camera cost a lot, but not nearly that much, not even close.
The old pinnacle of state of the art film camera the former company bought was $480,000 new 10 years ago and it might find a buyer for it at 25 grand now. Heck we had to send that film camera in to be cleaned and lubed and then get it certified by the USGS every three years for a cost of 20 grand. A 500 foot roll of film is $3,800 now and then a buck per foot to process it and then scan it frame by frame on a scanner that costs more than my house.