And a plethora of others. It just isn't economically feasible.
Well, it depends on where you are, actually. Here in southern Arizona, where the weather is virtually always clear and bright and sunny, a lot of businesses choose to install solar panels - with absolutely no encouragement/coercion from any government entity - because it really is cost-effective for them. Our local electric company has a program where they will rent your roof; essentially, they pay you a stipend every month to allow them to put solar panels on your roof and feed the resulting power into the local grid.
That being said, you're still going to need some sort of supplement for when the sun isn't shining, because even in the summer, when the sun doesn't go down until around 9 pm, we do still have nighttime. And solar power is still completely ridiculous for places like Seattle, where it rains so damned much you practically mildew.