Rooftop solar in the US is incredibly expensive from most installers even as panel prices have come down and energy prices are typically low enough that the payoff time and up-front cost are seen as not worth it for many people. The US also has a lot of homes where (cheap) natural gas is used for cooking, heating, and hot water, which you'd have to continue paying for even after you installed solar panels or pay a lot of money to convert to electrical equivalents.

That said, I know a lot of people who have recently installed solar panels on their roof and it's increasingly worth it from a financial perspective. The other thing worth noting though is that while cool, rooftop solar really isn't the best approach to installing solar capacity compared to grid scale solar farms on land which also tends to be abundant in the US.