An excellent way of explaining the problem to anyone who understands relational databases.
The way I've always thought about it is that the market is always going to see a fourth house for a billionaire as more valuable than a house for a homeless person, even though that's not a particularly efficient allocation of resources.
RE: Unconditional Basic Income would fix a systemic flaw in markets: they can't tell the difference between a lack of demand and a lack of ability to express demand