Good point, I definitively have thought about the lack of AI that speakers have nowadays. If things had evolved the other way around, we'd be having AI powered speakers already (perhaps even context/person aware speakers that - like Star Trek's computer interface - could mean a lot more...
That being said, I have a couple of Google speakers, and for the purpose of controlling smart home features and letting my family and me play music, ask about the weather forecast, or let it play the latest news it is a good product.
The most annoying is its lack of interpreting sound when there's a little background Noise and that it doesn't catch different phrases that mean the same. For that, AI would be a great benefit. Not to talk about giving it much more power and features.