Remember that Barrett Jackson is very keen how being clean and in good condition or a rare barn find vehicle for the most part. It's expensive and so are the people that buy from Barrett. They are usually collectors and/or have a fair chunk of change on hand for expensive toys.
A regular truck or one in decent shape or nice restored may no sell for that much. A basic piece of crap might be 500 bucks and a nice clean survivor be 8,000. It's the demand, conditions and value of similars that create the price on this kinda stuff.