End of innovation and efficiency gains
I think the electricity price idea is a red herring: all things being equal, for the same over time, power demand should decline as more efficient hardware is used.
The model is predicated that companies will find the move from CAPEX to OPEX preferable, especially as systems scale up: 100,000 servers will cost you more over time if you rent them, but you'll have to pay up front for your own. In addition, vendors promised that they would be the better administrators and would be able to squeeze greater efficiencies out of shared infrastructure than clients could on their own. However, it looks like that advantage disappeared a few years ago and has since been superseded by the hydra of complexity as the vendors have to manage more and more complex operations and abstractions. They're probably also introducing cross-subsidies to make their "AI" offerings looks more competitive: there are potential advantages there for those who don't offer them.