What do you mean by astronomical? My back-of-the-napkin estimate is that you'd pay about $8k a year in battery costs to supply a household ($20k 18kWh battery system lasting 5 years, then double it).

Obviously that's missing commercial power, utility-scale storage, heavy industry, electric vehicle charging, etc., but it seems like factoring those in would give you a big yet feasible cost, especially if storage gets cheaper over the next decades.