[jandrese]

True, but there are numerous other costs with doing industrial scale storage. You need to buy the land. Need to design and build the facility and interconnects. Need to do the permitting, environmental review, and other paperwork. Need to do the maintenance and deal with security. Building a facility like this usually involves buying all of the batteries at once, which is difficult in a supply constrained market like we are in now.

A sharing program foists most of this complication off on homeowners.