As you can see in the graphs I linked in upstream comment, in the UK alone, CCGT power plants have a capacity of 20 GW. That's 1000x this battery plant; meaning a $20 billion capital investment. And I don't see any way that Tesla (or anyone else) has the manufacturing capability to deliver that. Remember this is just for the UK, so for the US and Europe in total you're talking at least 10 000 plants like this.
Not all gas generators are peaker plants. Gas is displacing coal for what is often termed "baseload" (though I don't like the framing implied by the term).
The batteries will nibble away at the most expensive peaks first, the plants that run for only very short periods per year.
Meanwhile solar and wind will roll out to displace fossil fuel usage as well. Ideally they'll meet in the middle at some point, but it appears financially viable for this process to start now, and await further drops in pricing to expand later.
