Germany and many European countries are land locked which is a main reason why solar is taking off over there. Whereas in the US, we have plenty of land to build, sprawl, and otherwise disperse our energy use.
Solar won't work well for large cities; it simply can't produce enough energy for so much in such a small space. It can help, but the price point for a place like NYC, DC, Baltimore, Atlanta, etc, is that it just isn't worth the investment for the small return.
I don't know crap about the sun. I can't watch the video, but in reading it sounds like it was said more tongue in cheek than as a matter of fact.