I thought about this some more, and I realised, Tesla and other EV manufacturers better be praying that this is not a financially viable replacement for gas turbine peakers in general.
Otherwise there will be a big jump in demand for batteries, as power companies will be looking for hundreds of GWh of battery capacity. If they make a yearly profit for the power company that's significant enough to warrant the CAPEX of replacement, increasing the battery price by 10% only means one or two more years before break-even. So power companies could easily afford that if we assume the investment at current price levels is profitable for them.
That is going to significantly (negatively) affect the price developments of batteries and constrain supply even more than today, so EV manufacturers will be faced with either losing (more) money on each car or increasing prices and selling less cars.
Unless we assume Tesla is looking to pivot out of EVs in general, but I think that's a rather absurd assumption given their current actions.