I've found there are a lot of secondary markets that get overlooked by VC. Typically, these markets have (1) a lower ceiling so they're overlooked by VC's needing an outside return. They can still be massively profitable for a bootstrapped or lean company. (2) Require deep knowledge of two non-overlapping subjects.
Anecdata: I've seen three or four companies that look like this, one attracted VC (after proven traction), one was rejected cause (external risk) and the others are a nice tidy business for the founders and a few employees.
Sometimes I hear, pejoratively, a "lifestyle" business.
I've found there are a lot of secondary markets that get overlooked by VC. Typically, these markets have (1) a lower ceiling so they're overlooked by VC's needing an outside return. They can still be massively profitable for a bootstrapped or lean company. (2) Require deep knowledge of two non-overlapping subjects.