Keys and power are two separate dependencies, and only one of them can be dropped. A seed stamped into steel costs nothing to keep: it stays valid through any blackout, and no counterparty can touch those coins while the lights are off. Electricity buys the ability to move them. Ownership survives the outage regardless, because that dependency belongs to the network rather than to a custodian. Mining is the only seat in Bitcoin where the energy comes from you instead of being rented, and miners tend to buy the generators long before anyone else does.