Renewables come with major constraints that fossil fuel sources do not share. The value of the grid is rooted in its consistent availability. Renewables cannot replace on-demand generation because they are definitionally cyclic, constrained by availability of sun, wind and water [1]. Large scale energy storage is required to replicate the energy security offered by fossil fuel generation, which is not feasible with current tech at the required scale, and regardless the storage costs eliminate the argument of renewables as "radically cheaper".

[1] Geothermal is an exception. Gas is also technically a constrained resource, but not on a timescale relevant to this century.

You neglect the multiplicity of storage alternatives, all of which work, at different price points. The most cost-effective will be the ones used. Idiotic ones (e.g. Energy Vault's) won't be.

Of course very little storage is built yet, because it would be beyond stupid to build storage that there is not renewable capacity, yet, to charge up. Money is overwhelmingly better spent on generation capacity, first. Storage cost is falling faster than solar. When we build it, it will be very cheap.