I still think people are too focused on the idea that the lack of batteries is due to supply. I would argue it's due to demand. For most people there simply isn't an economic benefit for storage. Necessity is the mother of invention. As the benefit of storage increases we're seeing supply follow.
Back up storage battery Demand in many areas is through the roof. Not so much as great economic benefits, but to reduce the effects of local utilities turning off your power due to windy conditions and possible forest fires.
Tesla simply cannot make and install storage systems fast enough. There are also many government and utility rebates that help with the costs.
Buyers will spend the $ necessary to assure continous power to their homes and businesses.