Python is still used alongside C++ and Java (and some Go) but primarily for prototyping and small utility scripts. A Google engineer explains:

"Well, simple common sense is going to limit Python's applicability when operating at Google's scale: it's not as fast as Java or C++, threading sucks, memory usage is higher, etc. One of the design constraints we face when designing any new system is, "what happens when the load goes up by 10x or 100x? What happens if the whole planet thinks your new service is awesome?" Any technology that makes satisfying that constraint harder -- and I think Python falls into this category -- should be discouraged if it doesn't have a very strong case made in its favor on other merits."

And note this was before the failure of Unladen Swallow, before van Rossum's departure.