The Ethereum foundation kept a huge stash from the pre-mine, so you'd have a hostile actor with a large position on your forked chain, enough to crash the price of any nascent chain. This combination is a governance model rooted in game theory.

Ethereum Classic shows pretty well how this works in practice. There was controversy around the DAO, yet no fork could be kept functional. It is a Grayscale project which they will keep around as long as people are willing to speculate on it. Nobody pretends it has any real use.