Solar makes roofs last longer.
I though my array was going to be a hail magnet, but apparently the panels are more robust than the shingles -- both neighbors have had roof work due to hail and I've not. If I could find $10,000 I'm not using, I'd like to put another array on the west side of the house, then tie the A/C compressor into the system. No point in being without A/C just because my neighbors don't have power ...
Now back to the topic ...
The tree huggers do the work because they believe in it philosophically -- it's easy to work on the cheap for a cause you believe in. If you don't think making electricity with less pollution and less dependence on dwindling resources is a good idea, you'll want to make more money than you can make in solar.
That said, the money is being made by the large installation companies. Which become large installation companies by first being small ones. I've sorted out dozens of bad installations over the past few years and the companies that do bad work don't get more.
On the other hand, once you have a reputation, you'll get work. I do monitoring and power management work and I just got a contact from someone in New Zealand who needs to monitor 45 remote solar power systems. I was contacted last month by someone in Kansas about monitoring solar power for traffic monitoring systems. I sold gear to Lincoln, NE last year for a wind powered traffic light backup power system. I have equipment that the FAA is looking at for solar powered airport lighting. This is all in just two years since I decided to throw my hat in the ring. In that time I've seen a number of my client's businesses grow dramatically -- but they had been at it a few years.
What you can't do is go from being an electrical contractor to a solar installer next week. I quoted a system to a guy and the piece of work that didn't require solar experience was a $2,000 panel upgrade -- the rest of the system was about $20,000. Since solar installers have their own master electricians (most of the time ...) they can do the panel upgrade themselves. So, you're shut out if you think a leaky roof is a nightmare you don't want to deal with. And I've been on roofs, and up a turbine tower or two and survived.