Being rich/connected is great, but there's a third option: Show early traction.
Isn't that the point of those companies though, that you aren't seeing traction for a while? It could be that PG is making the distinction implicitly between revenue/profit and traction.
So for example twitter, FB etc... were not profitable or getting revenue well after they had already amassed millions of users. If that is the case, then we aren't learning anything new and it doesn't help people who are trying to make new, hard, breakthrough technologies.
If you've managed to gain traction with a service that has a clear business model (Twitter and Facebook would obviously qualify) then you are on the right track. Booking revenues is good but mostly because it demonstrates that you can book revenues, not because you actually need the cash.
I think one thing that rarely gets mentioned, is that startups get harder.
As in, the more traction you show, the harder it becomes to continue that traction, or alternatively, more traction is now expected of you. Combine this with the increasing complexity of a growing machine.
Maybe PG's analogy is that at first it starts off a pinch, but grows to be a very large guillotine until you finally can outrun it.
Absent other advantages, you will need to get to product-market fit pretty quickly if you want to survive.