Just compare it to any other car company, be it the Big Three, European car makers or BYD.f
The whole purchase of SolarCity was one of Elon's companies (Tesla) buying another company of Elon's that was failing (SolarCity) because it owed a lot of money to a third company of Elon's (SpaceX).
Tesla's most recent quarterly shipments are down 13# Y/Y with likely worse to come. The brand is being publicly torched by the actions of its CEO. A protracted trade war with China could end very badly for Tesla. A trade war with Europe may see the EU replace its demand for EVs with the likes of BYD.
Solar is (now) a commodity business. The panels get ever-cheaper. The only real cost is installation. And a labor-intensive cost like that doesn't scale.
I predict that Tesla will be forced to try and save itself by ousting its CEO in the coming years.