Money isn't an illusion. It is a useful abstraction of human effort/potential.

The workers will be fired because the boss has run out of societal-effort credits.

The only "illusion" is the collective understanding that these "made-up" credits can be redeemed with other counterparties for human effort in the future. So long as we all approximately believe that idea, it works.

> Worse: Money is an illusion. We mistake a unit of measurement (like grams, or gallons) for wealth. In a recession, workers come to a construction site - material is still there, so is electricity and power tools ... but work can't continue and they will be fired because the boss has run out of inches.

This is because the boss imagined getting more inches in future and made a leveraged bet. A downturn is a great opportunity for someone enterprising to become a boss and take everything in the construction site, hire people and build it themselves.