This means that the general level of trust in these machines goes down. After you lose your dollar a couple of times you stop using them. Aside from trusting official Coke or Pepsi machines, there's no brand loyalty (to the operator - a random name on a small sticker on the machine). So if your machines are well-stocked and in good working order, you won't do any better than anyone else. And after a while there are broken vending machines everywhere, which everyone ignores.
Interesting factoid. If you want to manufacture a machine and put large beverage company branding on it they have standards. Things like: it must bring a room temperature beverage down to xx degrees in yy minutes or less.
Isn't that still a branding issue?
Have a bright orange gorilla swinging by it's tail as the mascot. On both sides of the machine and on the front (though transparent enough to see the snacks without issue). "Wait, gorillas don't have tails?" you question. Exactly, that's the brand name: Gorillas Don't have Tails.
In any case, congrats to these entrepreneurs, and thanks for sharing.
Basically, the name of the game is location location location. It's very tough to find a good lucrative location to put your machine at. Why? Because there's likely already a machine in such location.
Also, it's a numbers game as many locations don't make that much profit per month. Therefore you have to have many machines, and getting 50-100 machines in great locations is no easy task.