Rooftop Solar Now and Then

Rooftop solar is going down the tubes with the lowest numbers since 2011.
Big deal?  Should we care and why?
Also, as Katie M. pointed out in her piece in the Star Advertiser that over 4,000 exemptions have been doled out to builders who have NOT wanted to install solar thermal systems in their new housing developments.  Why mandate solar thermal in new construction if you’re not going to bother to enforce the law?