Someone building a new building will look at roof design, construction costs, heating and cooling costs, leakage, and many other issues. It's entirely possible, maybe even likely, that a light-colored composite roof (it's more complicated than simply "painting" a roof) will turn out to be the most cost-effective measure.

In fact, companies that install such roofs are making a lot of money right now, and nobody is having to point guns to their customers' heads to make them do it.

To some people, every good idea needs to be compulsory. And one hell of a lot of crappy ideas, too. I don't understand that kind of thinking.