LiFePO4 packs already started trading below $100/kWh in 2020:
https://evilmartians.com/chronicles/a-no-go-fantasy-writing-...
CATL is pushing sodium-ion batteries:
https://www.reuters.com/business/energy/catls-new-sodium-ion...
You don't even need a lot of storage to greatly increase maximum stable solar and wind share.
Exiting times ahead of us.