May not matter if there's cash to make off with. Plenty of folks don't care about long-haul world domination or owning a market; if being a Significant Player for 3 years will earn them enough to retire, why not?
That's fine for you and many others. However, it's an anti-pitch for a YC company: demo day is really auction day. They're selling a chunk of themselves to an institutional investor sifting for disproportionate returns.