Digital definitely helps because you can just spam the hell out of the shutter. And I have no doubt that a shot like this has an obscene investment in equipment because I've seen the limitations of my own (still expensive for me, and realistically pretty decent) stuff. But the top end is something different.
Then on top of that equipment, you need some decent work into scouting locations where you can get close enough without scaring stuff away, you need to invest a bunch of time actually in those locations, with a reasonably high degree of focus, understand your camera and settings well enough to maximize the shot for the lighting, and react and get shots lined up in seconds a lot of the time.
Plus actually find a way to make a living on it or do it in your spare time between an actual job that pays the bills and for all your expensive gear. It's seriously impressive and there's a reason most people can't do it.