But fraud was involved.

Financially it was part of SolarCity bailout (Musk's cousin). It heavily heavily penalized Tesla shareholders and smelled of a family bailout. Solar Roof was announced so hastily in October 2016 justify the merger and stave off massive shareholder lawsuits. There was little effort in the roof development after bailout was a success, minus the bait-and-switch lawsuits.

There was genuine concept level development at some point, but it was developed into product after they knew it did not work to keep lawyers happy.