I agree that domain expertise is often lacking in startup founders, especially the "business" founder. For several years I wanted to form a recruiting startup

I agree that domain expertise is often lacking in startup founders, especially the "business" founder. For several years I wanted to form a recruiting startup without having built up a solid understanding of how recruiting works. After I had several years of recruiting under my belt, I was able to build a reasonably successful small business (originally a startup that couldn't scale) that exploited a nice little niche in the recruiting world. That small business wouldn't have been possible if I hadn't known a lot about recruiting.