Many do, as far as initial investment goes. It makes sense when you think about the capital intensive nature of most startups (including more than web startups

Many do, as far as initial investment goes. It makes sense when you think about the capital intensive nature of most startups (including more than web startups here, e.g. lab tech commercialization). It also accurately describes a research grant. That's for startups that can't bootstrap (most of them). For ones which can, they may still choose to do this with customers, as you describe, because it means letting their work follow the money.