Back at the beginning of the internet disrupting everything people used to talk about buggy whips a lot. About how once upon a time there were thousands of buggy whip manufacturers across the US and then cars, roads etc and they all suddenly went out of business.
Except, I always used to think, not all of them. I bet there are a few left. And I bet, if you can be the last one standing, you can have a very sustainable business. I always used to tell my advertising bosses that being the last great TV agency would be a fun and profitable niche (since they never seemed keen on doing the internet).
Ever since I've kept a little eye out for people who've made it through the demise of an industry and come out the other side. You know the kind of thing; record shops, typewriter repair, bookbinders, letterpress printers, minidisc makers, and now, it turns out floppy disk retailers.
These people tend to be interesting, because they're committed to something ancient and time-tested but they're also entrepreneurial and energetic. It's a good, rare, combo.