It would also be a lot easier if the majority of your machines were identical. The majority of vending machine products have a LONG shelf-life. So if you stock a truck with all of the things that all of your machines carry, you don't have to take the step that the article alluded to where you take stock and then go get the supplies. You'd just have all the possibilities on hand and restocking the truck only happens maybe once a week once you get a good idea of the flow of the individual products. It seems very feasible to me that 2 people could service that many machines. Especially if you're willing to work 12-16 hour days some days.

Assuming a time to restock of 30 minutes per machine, it would still require a workload of 90+ hours per week.

I guess a team of two could do that.