Why? In the context of the electrical grid, has the amount of storage you can have in the backburner ever been a choke point? If anything, fossil fuel power plants have the very same batteries to buffer some energy. But for the vast majority of power consumers that can just exist on the grid, power storage is nearly irrelevant because it can go directly from producer to consumer. Even in places where storage is relevant (anything that can't be tethered to the grid, like vehicles) the equation is different because the infrastructure you need to convert fuel to power (engines vs electric motors) don't weigh the same. Yes, even with that, pure electricity still falls behind somewhat, but it's getting better. And I was mainly talking about the power grid anyway, with how universal and important it is. Fossil fuel straight up loses in that sector, like what I said before, so replacing it is an easy choice... and yet we don't do that.