No one ever said that Lithium batteries were cheap, I even get sticker shock buying a cordless tool battery however did you see where a big battery beat all comers in a tender for backup power in NSW recently. There is a thread on it here somewhere.
Not too sure about your Tesla battery weights, the weight of batteries is directly proportional to power and the current Model S has 100kWh. The Model Y has 82kWh for the LR and Perf. a bit less for the RWD. If you saw a figure that said the Model Y pack weighs more than the Model S it must have been for the structural pack which makes the total weight of the car lighter than a conventional pack but should not extrapolated out for estimates relating to a big battery.
Now talking about a capitalist world surely you know about V2X. So long as they are plugged in anywhere compatible EVs combine their batteries to make a virtual big battery. It is a win/win situation, the power retailer has storage at a minimal cost and the car owner makes a few dollars with automated arbitrage power trading. Unfortunately Tesla and China haven't moved on V2X yet but Japan and Korea have so it is only a matter of time.
