Between GAssistant, Alexa and Siri Speakers I bet it’s a significant chunk of the population.

Sonos now have a voice assistant (far more limited though) and many cars are rolling out some sort of assistant too.

I know plenty of people with multiple speakers and from competing brands.

Oh and obviously every iPhone in the last decade has it built in. That’s 50% of the population right there. Then there’s android phones, where I don’t know if they all have it wakeword enabled, but it’s probably another big chunk too.