This where system thinking, or the lack there of, becomes an issue. You would be right if we only had exactly enough capacity for four hours of power. But of course with batteries now being produced by the multiple twh per year, each of them capable of cycling on a daily basis for a decade or longer, we soon will have quite a bit of battery connected to the grid. If you have a hundred of those four hour systems connected you'd blow fuses throughout the country if you dumped all that power on the grid all at once. That could be days of power under normal usage.

And grids can actually be connected together via cables now. The cliche is that solar panels don't generate at night. But if you connect grids via a long cable running east to west you can actually have solar power at night. And when you connect them north to south you can have solar power on a dark winter day as well. And when you add batteries to the mix (on both sides), you can keep those charged as well and use that power regardless of what time or season it is.

And that's ignoring wind (on and offshore), hydro, nuclear, and other clean forms of power that we currently don't use at scale (geothermal, fusion, etc.). If you add all that to the mix. And cables. And lots of battery. Grid connected car batteries, balcony solar, and all the rest, you end up with a lot of capacity.

Gas power is not going to way. But we probably already have too much of it and it shows in the poor utilization of existing turbines. Ironically, adding more gas turbines to the grid only makes that poor utilization worse for owners of these plants.