I mean, AFAIK basically the first thing Sheryl did when she joined Facebook (from Google) in 2008 was break ranks with the wage-fixing cartel and immediately hire like a whole infrastructure organization from Google. Many if not most of the early-ish-days hardass hackers at FB were (figuratively) still wearing Google T-shirts when they built FB's scale infrastructure.

So to anyone paying attention at that time, it was pretty clear that the level of tech cred should be about the same. It was the same people.