In Japan, Powerwall is also significantly cheaper than all Japanese maker batteries, last time I checked Powerwall's per-kWh price is only 1/5 of a Panasonic one. How could this happen?
Also Nissan Leaf price (3700kJPY/40kWh, without any grant) is closer to Powerwall (1200kJPY/13.5kWh, without any grant), despite Leaf come with full vehicle feature and V2H. I think Japan home battery market lacks competition.
Apparently Panasonic doesn't actually want to sell them.