I can see where that kind of business might have a following. I guess the guy has a generator to run the welder because not every location he goes to would have the electrical hookup he needs.
I saw a flatbed truck one day that was rigged out to do some sort of on site repairs. It had a welder, torches, air compressor, tool chest, crane for lifting heavy items or pulling motors, a vice welded to the rear bumper, and lots of other stuff for fixing things. Looked like he had everything he needed right there to do most anything.
There are a lot of businesses that people make a living at that we never thought of.
Don