I'm out of date because the 5D now has a 100,000 shot shutter and the 1DSmk2 has a shutter durability of 200,000 cycles, which is 30% higher than in the EOS-1D Quoting from Canon site. It is still all pretty remarkable stuff. The thing is, I'm pretty sure that if the catalogue house were using Canon or Nikon gear they would probably have the same level of equipment failures. Kit these days is pretty robust but that kind of round the clock usage is extreme to say the least. If you calculate the cost of film and processing they have saved by going digital then the cameras and lenses are probably seen as disposables or consumables.
Damien.