I don’t understand how anyone still trusts any off-the-shelf smart device. Even the companies that explicitly promise not to do something have been found doing it.

They 'trust' it for the same stupid reasons anyone trusts bad ideas, uncritically. They don't think it'll happen to 'them'. Same reason people drunk drive. Same reason people smoke. Same reason people have unprotected sex. Same reason they do anything. It only ever exists as an abstract notion until the crosshairs visibly point in their own direction, and they suffer consequences as a result.

I thought I took privacy seriously as a person that's fairly conscious of it, until I turned my own, 'advanced', layman OSINT skills upon myself, and was shocked at what I was able to uncover. In detail; incidentally. And I was never prompted to do that, until I lost a job opportunity which involved an extremely 'extensive' background check, that included a 'highly' speculative interpretation of a few key events of my life, which were completely inconsequential.

And most people will continue to behave the same way, until something similar forces them to revise their prior thoughts on it. It's like thinking you're going to defeat prostitution through moral lectures; and you won't. Not until people experience loss or pain. Pain's always a more instructive teacher for people, because pain always raises the question of 'why' it's there. It forces you to think about how you ended up where you are. Unfortunately, most people are just blissfully ignorant.