> These numbers are ludicrous.

They are also speculative, not real. They are based on the notion that the company would be worth that much based on projected cash flows, expenses, etc. If you actually tried to cash it all out at any point in time you could not get anything close to that because the very act of selling will lower the value by destroying confidence in the speculative valuations.

None of these SV billionares have billions in cash or cash equivalents. Maybe a few of the largest companies do.