I'm curious if you guys who are so scared of the data collection via Alexa / Google Assistant / etc. use Facebook? This is a serious question, because I know a ton of people who are hesitant to use any of the free services for this reason but then share every waking moment on Facebook. Even with not making that information in a public post, that info is easy enough for someone to obtain. And man, I see people sharing that awesome photo from the top of Vail or at the local Football game. Well, hey there, thanks for advertising you aren't at home...
As for the devices getting hacked, technically possible, I'll give you that. But I trust a Google or Amazon or Apple over HikVision and I let them at my house (not inside!) Also, if you look up the Bluetooth enabled door locks, nearly every one has been hacked. But I would use them if I ever need to change because if the criminal is going to that length to get in, well, you are screwed anyway.
I would agree with the couple of people who say they trust Apple with the information more... although I do think Google and Amazon are doing a pretty good job of keeping their troves of information within their companies. Facebook does not. The other companies that people tend to ignore are their cell phone providers. Most are quietly building a HUGE database of your usage and history and, as far as I know, the only way to defeat that is to use a VPN service or a Tor-like client.
Adam