I'm pretty sure that Google replaced a shortcut for the hardware buttons on my phone to open some kind of Gemini interface in a security update and I had to change it back. And Gemini was auto-migrated from Google Assistant as the default digital assistant at a similar time(?) That alone would account for millions of users interacting with the app accidentally/unwittingly.

So as usual with these type of consumer choice/preference claims, it's sensible to be cynical. At least the Pepsi Challenge couldn't secretly swap out your water tap at home for a soda fountain, record you drinking it and claiming you prefer it to Coke. https://en.wikipedia.org/wiki/Pepsi_Challenge