Optimised current cells, next-gen cells, and next-next-gen cells are all projected for similar price per kWh (one that makes any storage approach more than "buy us time to spin up a burner" impossible). For the record, that's now what I've heard from:

private market analysts, government strategists, and scientists.

As always, please show me a credible plan that says otherwise. I would be extremely happy to be proven wrong.