"[5] If you're building something for which you can't easily get a small set of users to observe—e.g. enterprise software—and in a domain where you have no connections, you'll have to rely on cold calls and introductions. But should you even be working on such an idea?"
When pg says, "Should you even be working on such an idea?" -- is he saying that he questions any startup that is focusing on enterprise and which cannot be sold to fellow founders in a YC batch?
He once wrote "enterprise software companies sell bad software for huge amounts of money", so I suppose he doesn't love enterprise software that doesn't have a long tail customer base.
But, wouldn't this exclude a lot of interesting ideas in education, healthcare, government, finance, etc.?