Yes, they had been successful with voice search long before Alexa ever came out, and continue to do it well. Google is THE search giant, you'd have to be acting intentionally obtuse to not understand his point.
I'd guess that 20% of Google's mobile queries in 2016 are a few orders of magnitude larger than Amazon's total voice search queries, effectively making Amazon's voice queries a drop in the ocean.
Long before voice assistants/search became a thing with smart phones there was Google 411 ... which no one remembers.
https://en.wikipedia.org/wiki/GOOG-411