He isn't saying making solar panels is a bad idea. Rather, he is pointing out that, at the time of the interview, solar adoption in the US was limited by instal

He isn't saying making solar panels is a bad idea. Rather, he is pointing out that, at the time of the interview, solar adoption in the US was limited by installation capacity, not production and management capacity. SolarCity has been working very hard an effectively on installing and managing rooftop solar systems, so it is possible that they are not limited on the production side, or that they have enough volume on the installation side to justify vertical integration.