It's getting pretty hard for anyone to make the case that Ethereum isn't a giant bubble. What makes this coin worth a billion dollars?
Selling all the ETH will never net $billion. Maybe $10 million before the price is near 0 due to the selling.
Market cap is a misleading metric.
More relevant is volume, except we have no way to know what percent of the volume is real versus insiders buying from the themselves to pump the price and volume up.