Why is one guy cornering the market on the 1964 Curt Flood baseball card?

ESPN:

A low-quality copy of the '64 Flood goes for about $30 -- more than five times what it should, Klein estimates. A pristine copy costs upward of $1,000. Such prices defy logic; while the Cardinals' center fielder was an exceptional ballplayer -- Flood won the Gold Glove seven times -- he was no Mickey Mantle. Flood is best known for challenging baseball's reserve clause, spurring the creation of free agency.

The case of the '64 Flood has befuddled card hounds for years. A blogger who chronicled his pursuit of the entire '64 Topps set called it "one of the more perplexing cards" in the collection. Numerous message-board threads pondered the riddle. "This card was a pain," complained one collector. Others said they had heard a single buyer was gobbling up inventory. "Perhaps he's just absent-minded and forgets to cross that card off his want list," someone offered. Klein wrote about the '64 Flood for Sports Collectors Daily, noting that it had attained "mythical status."