Accurate title: our Safari users have faster load times than Chrome or Firefox users.
And the author's theory that they're wealthier, have better access to high-speed internet, and/or have newer machines is probably enough to explain it.
I could not actually find any such differences when doing segmentation by geo location. So I don't think that's enough to explain it.
Fail fail fail
Safari doesn't support navigation timing api, you are not comparing apples with apples, just showing off the failings in your analytics provider.
The navigation timing API seems to work in Safari 8 (Yosemite).
hmm, it seems to work just fine. why do you think it is not supported?