Hey, here's a pleasant thought!
He's actually buying 5K print runs for each deck - but he's DESTROYING large percentages of each run and using them as landfill, compost, etc. This way he makes his decks that much more rare, leading him to believe they're that much more valuable.
The price run-ups on his decks? I strongly suspect shill-bidding is going on - he bids against his buyers using a different account, or worse, creates more than one new account and is bidding against HIMSELF just to set a high market price based on his "sales".
He's a hack, plain and simple.