Guarantee this: most of the land won't be sold anywhere near its valuation. There won't be enough money raised to pay for the auction. The FedGov will also retain the right to tax the property, and will retain subsurface rights. They also won't auction national parks, wildernesses, or forests. Doesn't leave much that anybody would be interested in. Maybe later, when there are 6 billion people living in America it will be worth something, but not now. It's just $6 trillion collateral.