Curious, it’s all about how often you change lenses and what apertures you shoot at. The guy in the video uses prime lenses and has to swap lenses every time he wants to change focal lengths. Think about every time you change the zoom on your lens, and imagine having to swap lenses every time instead. That can really add up, and as a working photog he does a LOT more shooting than you or I, so the lens changes add up even more.
He might also do a lot of work at smaller apertures such as f/16 and above. Dust is a much bigger problem at those smaller apertures than it is wide open.