I think along these lines every day, and not just for game-used bats (although they are a great example...)
So many forms of memorabilia are rarer, closer to the game, and display far better than cards. The price disparity makes no sense to me. How can a jersey worn by Hank Aaron be worth less than his rookie card? There are thousands of his rookie card available, and it's a small piece of cardboard.
The Jersey was worn by Aaron while he competed in actual games. But unlike the mass-produced cardboard rectangle, the Jersey was literally a part of the game. Same holds true for Bats, Caps, Jackets, Helmets and Cleats that sell for a fraction of the Card's worth.
I will never understand it, but am glad the pricing disparity has made it possible to amass a collection of these iconic artifacts. I keep thinking the collecting public will catch on, but lately it seems to be going the other direction!
