When has that ever been the case?
Just because some company says "We do X", you shouldn't fall for the trap of believing them.
All of the FAANG companies say the same thing, as do quite a few non-FAANG companies.
Not the OP, but let me reframe the point here: I do not dare to say that Google hire the best; but what they goes quite close to get the top talent from some demographics and with certain skills and give the resources, some amount of freedom, and guidance and then collect the astonishing research results.
Personally I do not think that Google Brain has more talent than TU Berlin/TU Munchen, but the main difference it’s that the former has more access to resources and certain amount of intelectual freedom to spend a bit of time in something.
End result: The top conferences in AI, Machine Learning and so forth are dominated by Google and other big companies.
the best would also relate to the size culture, goal of the company, existing products etc etc
why would the best seek employment? i chat with a guy who claimed to charge 5000 per phone call, he would be much to busy studying to even consider employment.