Here's a novel game idea, that might also increase land liquidity. In order for a Soulbound card to become manifest, it must spend a certain period of time staked to land (without an unstake) - meaning it essentially has to do a period of "servitude" under the original owner before it can manifest and be traded.
We could then also track a variable like (days_Staked) for each card and award those who have the longest service histories without movement in the future. (perhaps a logarithmic bonus the longer it has been staked, up to a limit?)