Rather, I think this is more evidence of the old "Good programmers will be productive in any language." The advantage that an expressive programming language like Lisp gives you is that it frees you to think about the problem domain and not worry too much about the details of the machine. However, if you're skilled enough that you've pushed those details into unconscious muscle memory, they don't matter anyway. And a language like C++ gives you the option of dropping down to the bare metal if the need arises.
There are a fair number of Lispisms in early Google code - MapReduce is the obvious one, and there're others that I'm not at liberty to discuss. However, they're Lispisms implemented in C++, where the author took the concept and transplanted them into a language that could give the efficiency needed. This is not a bad strategy - when you understand the concept fully, you're free to tweak it and adapt it exactly as necessary for your problem.
Perhaps not coincidentally, many early Googlers were also programming language & compiler guys before Google. Urs Hoezle (employee #9 and Google's first VP) had previously done StrongTalk (statically-typed SmallTalk), Self (the prototypical prototype-based language and an early inspiration for JavaScript), and the VM that later became Java HotSpot. Jeff Dean got his Ph.D on the Cecil/Vortex compiler, one of the first optimized implementations of CLOS-like multimethods. Rob Pike worked on Plan9 at Bell Labs and invented the Limbo programming language as part of it.