It is and it isn't. I have a friend who was a professional (wildlife, among other things) photographer in the days of manual cameras. He carried multiple camera bodies, and _very_ expensive glass, but his real secret to getting the National Geographic Shot (which he had done, for real; as in printed in the magazine, back when that mattered) was to shoot a lot of film. And by a lot, I mean a lot. Like, routinely more than 1k frames a day.

Which is to say, whilst those constraints were / are real, they are mostly to do with money, and those who weren't constrained by that got the best results.