In the US, it's due to the cost of the grid, the part of the utility bill that PUCs allow utilities to charge a fixed rate of profit. So if utilities take 20% on that grid "maintenance" project, the utility drives up the price as high as possible.

This is why distributed solar is actually cheaper than utility scale solar all-in: you need less of that very very expensive grid, even if you pay 3x on the initial install costs.