I think that it is probably fair to say that the successful sale of our mandarins as kids was less due to their fresh and cheap nature and more to do with the fact that they were being sold by a bunch of kids.
I doubt a bunch of adults would have as much luck selling fruit, or any luck at all for that matter. This doesn't mean we didn't have a money making business, what it means is that the execution of the sale required a unique offering and (arguably) an inflated value proposition delivered by a sales team that was very hard to say no to.
Some people are better than others at selling, but just about anyone can make this work if they want to, you just need to find something that suits your style.
