Installing on people’s houses isn’t just about install costs (the numbers for which above I highly doubt). There’s a huge additional benefit, and cost reducing factor, that comes from installing storage where grid connection already exists. Instead of building out battery farms in the desert and piping the power into urban centers over cables like a power plant, you can install capacity and run it essentially p2p. This is a big deal.

I’ll add that we’re not DIYing this. Professionals are manufacturing and installing these at scale. Also, though I’m not sure how it works outside the US, the government doesn’t build the grid. Energy providers and utilities are also companies.