This is an incredible feature of Bitcoin, which exists only because it is a single market, in which every miner competes for the same exact finite resource (new units of bitcoin). Thus, a new unit of hashrate no longer empowers existing miners, economically,speaking. If enough sustainable units come online, especially if they are subsidized (and so the equilibrium for hashrate is higher than it otherwise would be, at normal breakevens), some regular miners with a generic energy mix will no longer be profitable and will shutter their operations. Few other industries are this directly open and competitive.
