Obviously our debts exceed this, but that's a different issue. Say everyone cashed in at once - they'd get a percentage of our debts, not zero, since there's still material value.
You can't "undo" Bitcoin's power -> money exchange, though. There's no gold sitting in vaults providing some real, physical insurance. If I lift this brick, I've done work (but nobody cares) but even that has intrinsic value as it can be "redeemed" by lowering it, powering something. Bitcoin is different.