Depends on what you mean by a pro. When I was doing architectural photography, I took far fewer shots in a year than the typical amateur would shoot in a day. The whole point was to get it right the first time. Most of the work was up front evaluating the shoot, balancing the lighting, careful positioning and metering, and so forth - no time left over to waste on redundant shots. That's not the case when people are guessing or bracketing and so forth. Now with digital cameras, the number of "hope I got it" shots seems to have increased tenfold, pretty much the antithesis of professionalism.
Pretty much the same story with studio portrait pros, or even skilled environmental portraitists. Not everyone drinks 39 cups of coffee before a shoot to hype a machine-gunning mentality. But don't get me wrong; we need more machine-gunners to keep up the volume of film sales.
What about a wildlife pro? - yeah, they might rapidly shoot an opportune sequence when it arrives, but might have to wait for weeks in a blind for that to happen. And then that opportunity might last less than half a minute.