You'll find a lot of one-person businesses targeting tiny, but profitable, niches like mine. What's great about it is that often when you find a tiny opportunity, it opens up a lot of other problems that need solving that you would never find otherwise. It's also a great way to learn the skills of running a business in a relatively stress-free way (at least compared to running a startup).
The only downside is if you're anything like me, you'll get antsy working on small projects and yearn to tackle bigger, more ambitious problems. Sometimes 1-person companies have the potential for turning into a company with startup-like growth, sometimes not. I'm still trying to figure out how far I can take my company.