I am not using the wrong metric. You can convert any asset to money given enough time. I am not saying they have to make an attack within a certain deadline. And I am being conservative, beacuse you could even get a loan to make the attack, so even more people would qualify.
It's just that net worth is a figure that's easier to fudge. Cash is cash. Assets can be over valued on a balance sheet or liabilities can be under valued. I'm not really trying to argue with you, like I said I get your point, I'm just saying liquidity is probably a better measure as to someone's capacity to destabilize a market. Good point about using leverage.