Electricity plus some small premium should be tenable under any market condition. At least it works for public clouds so far even as hardware prices have fluctuated over time. There will likely always be someone who'd rather briefly rent than buy.

I do wonder if what's charged for electricity and premium can be competitive with large data centers in the long run. Amazon already has spot pricing. I expect it would be favorable for consumers with cheap electricity or who are already paying to heat their house.

I also wonder what effect renewables increasing electricity spot price volatility might have on this market in the future.