Since I know you didn't look at the auctions, all of these trophies were obtained between 1990 and 1997. He's hung up his hunting rifle, which is why he's getting rid of a ton of his trophies. Nothing I would ever even think about buying, and I wouldn't understand why anyone else would either (why own someone elses trophy), but at least the money is going to charity. It's not like he's lining his wallet with this money.
Also, becoming a millionaire doesn't take the hunter spirit out of the person... it just makes them want to bag an even bigger prize.