(2) Most all of the "smart" TVs in my area don't use any of their features. They are all used as dumb monitors. They either take signal from a proprietary cable box, a game device, or some other media player.
(3) I have yet to see a TV that requires an internet connection to function. If you have one of these things, blacklist it on your network. At the firewall, or just don't give it your wifi password.
If I watch a Blu-ray or Netflix, my smart TV will still send a fingerprint of that content to their servers for analytics.
As far as not connecting your TV you the Internet: (1) The default setup says you need to, so most people will since they want to watch Netflix. (2) There's so much free wifi around these days I wouldn't be surprised if TVs try to connect to any open wifi for "automatic updates".
https://infographic.statista.com/normal/chartoftheday_13191_...
The statistic you're citing lumps together people watching directly on a TV vs using it as a display for a device like a Roku or X-Box, so it doesn't actually support the point you're trying to make :)
Admittedly, it's been a while (and a couple of Apple TV 4k software revisions) since I've checked, but as you get into newer display technologies it's harder to find devices that can provide you the same experience you'd get from the built-in app.