Congratulations to them for perfectly nailing every exposure in camera, and never needing to make any corrections after the fact.
Sarcasm aside, shooting in raw gives you much more flexibility in post-processing, whether it's to correct for uneven lighting, clean up a shot with very high dynamic range (very night highlights and very dark shadows), or just fix the exposure because you had the ISO set one stop too low, and your subject stepped from the sun into she shade before you changed settings. It also gives much more flexibility in noise reduction, sharpening, and color correction. If those other photographers don't feel the need to do any post-processing work, that's their choice. For anyone who does do post-processing work, having a raw file is a boon.
Having said all that, making top-notch photographs, and being technically proficient in all forms of shooting, lighting, and postprocessing... all that is good and well, but it's not necessarily the same as being able to run a successful photography business. Some folks can have a very successful business with very mediocre photography.
Of course, there are also plenty of people who run a very mediocre business with very mediocre photography. The weekend warriors, the Uncle Bobs, the GWCs, and the bored housewives. At the risk of sounding like a jerk, I'd wager that most folks who say raw files are a "waste of space" probably fall into that sort of category.