To date the market for these things simply hasn't had traction, at all, despite it being a long term dream of many display manufacturers. They also cannot resist the urge to go all in on inevitable privacy invasion stupidity, because they believe all the others will do it and so undercut them.
Oddly the generative AI wave is exactly what the marketing people thought they were missing when I was involved, since they wanted you to be able to describe something and have it just appear. Now you actually could.
I see a lot of blocked requests in my OPNsense firewall (not sure what exactly) but I see that with almost all 'smart' devices (which I like to keep local).
The system I worked on never had fans in, but was rated to operate at 75C instead.
I thought the whole “your devices are listening to you in order to display ads” myth had fallen out of popularity
You mean the media stopped talking about it - it has no relation to whether it happens or not.
Also 99% of people don't even know how to do this, and of those that do, 99% won't bother.
You quite literally can't tell by watching one what it is doing. You certainly cannot verify that all Alexas are not doing something.
But as for actually using it as a picture frame - no way. I think it's the reflection of modern rent culture where landlord put these things in along with generic Ikea furniture, allowing tenants to 'customize' their living spaces without being allowed to drive in a single nail.