I'm confused by your comment. Sure Apple, Microsoft, and Oracle are older established companies but from everything I know about Apple and Microsoft their stories seem very much to fit the startup mold (don't know much about Oracle). And the other three Zynga, Facebook, and Uber are comparatively much more recent successes that definitely took the standard seed funding to VC route and embody everything you would think of as a modern startup.
So you're saying that this doesn't apply to super successful startups? Honestly that's not been my experience, both personally and from plenty of stories I've heard from the more "modest" startups that have been successful but not on the same grandiose scale these companies have been.
In PG's view startups succeed because they actually create some real value, something that other people want. And to build something like this it helps to be nice.
Maybe I'm naive, but it's hard to say that PG doesn't know what he is talking about when he talks about startups :).