Yes, they managed assistants badly - Google, Apple and Amazon. They could have added more APIs, recognized many more patterns of user requests, and it's just plain old programming, so what's keeping them?

For example, Google Assistant doesn't play nice with YouTube. I guess it isn't in Google's interest to have a free agent software serve a free music site when the same service makes money for Amazon (Alexa). They wanted to make their agent profitable, so didn't let it be extended for free. Just my guess.