These are topcon modules only. Considering a 400W panel will have about 72 modules in it, that's only about 15 panels worth. Of course, then you have to actually build the panel and connect the modules, put it behind glass inside a frame, then put in a bypass diode and leads for connection. So an actual panel ends up being about 5-10X the cost of the modules per W.

Thousands of people buying rooftop panels was never going to be the best way towards a Water/Wind/Solar (WWS) future. Fitting panels to the roof has to work around the roof geometry and obstructions like vents. That makes every job a custom job. It also means thousands of small inverters rather than a few big ones.

Compare that to setting up thousands of panels on racks in a field. As long as it's relatively open and flat, you just slap those babies down. You haul in a few big inverters which are often built right into shipping containers that can just be placed on site, hooked up, and left there. Batteries need inverters, too, so if your project includes some storage, then you only need one set of inverters.

I get the feeling of independence from the system that solar panels on the roof gives people, but it's just not economically the best way to go. The insanely cheap dollars per MWh of solar is only seen when deploying them on a mass scale. That means roofs of commercial/industrial buildings or bigger.