Indeed they are. My wife's dad has created a device that measures some welding parameters. He sells it with really old robust laptops

and a very simple DOS program. Hey it does the job well for a welder and they don't ask for more. He says it's a smart measuring machine and he sort of can live well on selling it and supporting it (he does other things though, also welding related but that's not the issue)
I asked him once why he doesn't patent his product and he replied exactly as your reply. He also added that his product is "safer" non-patented.