His memory which is obviously better than yours
The point is, puzzled/Rich, the United States is huge. There are an uncountable number of municipal utility districts, deed restricted communities, city governments, county governments, etc. all with their own rules and regulations. I can't remember a place I have been in the US where I haven't seen solar power of one form or another. Yes, some building codes may be more restrictive than others, or some community deed restrictions may consider certain types of apparatus added to homes in their area to be eye-sores. But, you cannot brush the entire country with the same brush stroke. Every area is different. There is no single US law or restriction that keeps people from embracing solar power.
The reason SOME people have chosen not to go with solar power in the US is that there is no financial incentive. In some areas, it is not feasible at all because of local weather patterns. However, many people use solar power/heating in the US, especially in the south. I haven't seen it as a problem, even when they have to abide by a local ordinance (which you must do whenever you build anything onto your home).