We'll also see micro-storage developing to take advantage of electricity price variability. EVs will charge when electricity is cheapest, household water might be warmed during the day when solar energy is available, etc.
Unfortunately losing nuclear means that we lose the potential for a self-sufficient regional grid. But since the costs of losing base load power are largely offloaded from national budgets, instead showing up as new costs for consumers and companies, it's a lot easier for a politician to advocate for renewables. No need to spend taxpayer money on a project that won't be finished in the 4 years that matter to your government.
But we don't need 10x overbuild: the wind is always blowing somewhere. If not here, there. If not there, here or somewhere else.
No breakthroughs of any kind are needed for grid-scale storage. It is just civil engineering. It won't be batteries.
Nukes have never, at any time or place, anywhere in the world, operated without massive public subsidy. There is no reason to expect that ever to change.