I think you know that I've always agreed with you that vintage collectables of all sorts absolutely represent an investable class of assets.
However, the part I bolded is the problem in your argument. You don't own any part of the actual book, your shares simply represent your portion of whatever the fair market value is determined to be at any given time. If memory serves, someone previously pointed out that if Rally were to go under and wipe out all the shareholders in their assets, the shareholders have no underlying claim to any liquidation proceeds.
Joe Pesci's speech in My Cousin Vinny about rebuilding a carburetor immediately comes to mind.
Ultimately, you're no more an owner of the book than the average nobody on the street who has never heard of RallyRd. Plain and simple, its a play for profit. And there's nothing wrong with. No reason to pretend otherwise.