Clearly Quint was using the wrong tool for the job. If the best you can do for the line is 1000lbs test, your great white is gonna just snap it off like a twig.
He does get to shoot guns that aren't up for auction. Getting hooked up with these auction houses was the best thing that ever happened to his channel, as he is able to get his hands on things so rare that they essentially don't exist in the wild... even if he doesn't get to shoot them.