Vending machines are great business.
You have the merchandised in an armored box, thus you don't have to account for the minor petty theft. And, you don't need to hire a attendant to sit their and take money.

Further... you lose out on human service using a vending machine... but actually helpful store people are a dying breed.

Well, maybe, the next step is actually improving vending machines.
So long Wallymart.