[xyzzyz]

So where are you going to get that much land close to people so you cheaply transport it?

Why would you need the land to be close to people? Electricity transmission losses over 100-200 miles are minuscule, and there's plenty of cheap land in the radius of 100-200 miles from literally any point in the US.

[bluGill]

cheap land can still be expensive. For the rooftop it is a sunk cost and so "free."