I enjoy the show very much. Pawn shops are what they are, they perform a service people want or they wouldn't be in business. It's the free market at work. The guys on the show are paragons of integrity compared to most pawn shops, and are extraordinarily up front about what they'll pay and why.
Looking at it from their point of view, why the Hell would you loan anyone (Or pay to buy) what the customer had at more than about half to two-thirds what you thought you could get for it? You'd be broke in no time if you paid or loaned more than that proportion of its possible auction value -- it's a business, not a charity.
It would be totally nuts to loan more on something in pawn than you would pay for it outright for resale; if word got out that you did that, nobody would sell you anything outright, because they'd realize they could pawn it, forfeit the pawn, and walk away ahead on the deal. Meanwhile you'd be stuck holding it for the full term to forfeit, which is dictated by law in most states.