And it hasn't really changed since 2016 so that is still mostly spot on.

I think the real problem though is that people aren't good at remembering voice commands, either how to invoke the command or that the command even exists. Without visual cues it's easy to forget everything.

You're not going to have a runaway hit when it's predicated on everyone remembering that special thing to say. It's like trying to have a runaway hit that had to be based on a keyboard shortcut.

All of those services are great for the basics, e.g. How's the weather / set a timer / remind me in N minutes / order toilet paper ... Everything else is a bit tougher in my opinion.