Sellers like that have buyers that have means to part out/ fix or have means to refine themselves. Remember not everyone is buying oranges like you. Some people are buying apples* (pun intended). In all seriousness, I've learned from a similar situation. The process in which one buys and resells is different from person to person. If youre comparing apples to apples and oranges to oranges then there is a profitability ceiling.

More than likely they have found an avenue different than yours as far as resale value.