It's like every lesson about not disrupting GUI flow with modal banners, and about creating shortcuts and other accelerated paths for advanced users was forgotten in VUI. At best you get a one-size-fits-all brief mode that usually isn't very brief, and doesn't reward learning so doesn't increase engagement.
VUI vendors also plainly have no clue how to enable discovery without either fucking up your home screen with some ugly "things you can do" list or being annoying about volunteering stuff when responding to your commands. It's as if they might need to *gasp* document their features instead because voice devices aren't web apps you can just fiddle with.
The net result is I actually get way more frustrated with these devices now that I'm super-experienced with the tech, not less. That's the wrong direction.