A guy at my wife's office has a single pop machine (cans only) on the first floor of a 3 story bldg, maybe 75 people total. He sells them for $0.50, and still makes maybe a hundred a month. Restocks before work twice a week. Probably not worth the time, but he does it so he always has what he wants available. And he takes requests.
Family friend used to have a network of air pumps all over, several hundred at the peak. He did very well, it was his full time job. The money makers were in the worse parts of cities, but vandalism/theft was also much higher. He collected from them every day, and he went armed. So many quarters...
Decades ago when I worked in manufacturing, there were 4 machines, candy and pop, that were an absolute gold mine for whoever owned them. Sold out every day, people would time their supply walks to be first 5 at the machines at break time. I'm sure it's still the same.
TL,DR. Yes, it's doable. Small or large scale is up to you.
