It's facetious (and bad 'journalism') to claim $100B vanished. It was never there to begin with: market cap isn't something you can cash in on. It's merely the result of price multiplied by supply. If you owned a significant portion of all the coins in the world, and tried to sell them all at once, you wouldn't end up with number_of_coins * price, it would (realistically) be a smaller number given the market slippage…
until of course you can take a loan collateralized by the asset. Or get/sell some CDS/future/option based on the asset - that way you can even work with amounts larger than the market cap.