That sort of facility will have diesel generators for backup power, they will be maintained and tested monthly, load banked yearly.

Even if the generators failed, renting a trailer mounted diesel generator costs much less than $200/kWh.

If you really want to turn everyone who runs a facility that needs power for under $10/kWh into an energy trader who has to build a facility with a larger generator than needed and a battery bank and everything else, there is a huge amount of economic loss involved in that. Energy is cheap. Energy should be cheap. That infrastructure should remain for disasters.

Running those generators is not free, and puts wear on them. Also, starting up those generators takes time and puts a certain amount of wear on them, so you are now talking about also having batteries and other equipment to cover short periods and the gap during generator startup. And now when do you spin up the generator? Do you spin it up when the instantaneous price of a kWh goes over a certain threshold or do you wait? All of these are now things that every single industrial facility has to think about.