Earlier quoted context omitted.
I feel this fundamentally misunderstands how each of their AI's work. You're describing an interface problem. Google's AI is extremely good at recognizing speech in comparison to Siri but that's a wholly different thing to deep understanding. Siri is a more advanced AI in many ways due to it's understanding of intents. Google's is much more command based (under the hood). However Apple's speech recognition is letting…
This runs contrary to the experience of most people. See http://www.businessinsider.com/siri-vs-google-assistant-cort... Siri is dead last. Surprisingly, Cortana did quite well (I didn't realize Microsoft was catching up in this space). Those responses require a lot more than just voice recognition - they require an understanding of context and "intent".
> A recent study […] asked the major voice assistants 5,000 general knowledge questions
General knowledge questions is just one of the many things you can use voice assistants for. It's well known that Siri is the worst at general knowledge questions, but that doesn't mean Siri is the worst digital assistant.