I don't think this makes sense, it's a feature that makes their platform more valuable even if not directly monetized. There's many features like that.

If someone would nail voice assistants that would be a bit selling point for their platform and it's a good way to get people into their paid services too.

Not really sure what you are referring to with driving the assistants in the ground, from what I can tell it's just not very good tech ("one moment", "working on it", "there was an problem answering this query",...) and not related to any monetization strategies.