You are missing cost of materials, insurance, licensing, back office staff, marketing, cushion for slow months, opportunity cost, maybe franchise fees, training

You are missing cost of materials, insurance, licensing, back office staff, marketing, cushion for slow months, opportunity cost, maybe franchise fees, training, etc. Basically all the costs of running a business. You don't just throw a few laborers on a roof and call it a day. I don't know the actual overhead on a solar install, but if a contractors markup too large they'll lose out to the competition fairly quickly.