I think the main problem is probably finding any mainstream consumer TVs that are non-smart. I have looked and beyond some obscure brands or short of incredibly expensive commercial models there are barely any options.

Any TV is stupid if you don’t connect it to the Internet.

I haven't bought a TV in about ten years and I've started shopping recently, knowing I'll probably have to get one soon. What I'm interested in, knowing I'll probably have to do this (smart TV with no internet), is what the out-of-box experience is without internet.

Will it have preloaded ads that will never change because it can't download new ones? Will there be huge gray boxes where the ads should be in the UI? Will it try to connect to open WiFi or use HDMI to share my streaming box's internet connection? Will it nag me with an alert box in the middle of the screen asking me to connect it? Will it disable features if I don't give it internet access? Will there be bugs and performance problems requiring me to update the firmware, and if I do, will that firmware update introduce any of the above?

From personal experience, Roku OS TVs (TCL mostly) have a very good non-internet user experience, with a dedicated mode for being a dumb display. WebOS (LG) is decent. Tizen (Samsung) ones are okay, although the one I have is from before they started putting ads in the menus so I don’t know if there are placeholders. None of them have disabled any features or nagged me, or tried to sneakily connect to the internet. Google/Android/whatever-it’s-called-this-year TV (Sony) might not even be usable without internet, I’m not sure. It’s also terrible.

Generally, firmware updates on modern TVs are used for creating bugs and performance problems, rather than fixing them. They also add advertisements. Don’t ever connect it to the internet, and it’ll be fine.

I'll give you my anecdotal experience with a TV that has Amazon's FireTV built-in. It is disconnected from any network. It allowed me to set a setting that says "remember last input" so it always looks at a particular HDMI input for signal when it's turned on (because I always have it set to viewing input, not the smart interface itself). Set like this, it essentially acts as a non-smart TV.

The only downsides are that, being a smartTV, even in this pseudo-non-smart mode, if the TV loses power (rather than just being in an "off/standby" state) then it takes a bit longer for the TV to start up the next time. I wish I could avoid a TV having a "boot sequence", but my experience is close enough to a non-smart TV that it works for me

This doesn't answer all your questions, but the Rtings search tool can filter on whether TVs are ad-free: https://www.rtings.com/tv/tools/table

Sadly, that assumes the TV will behave and not connect to open networks, or use companies' mesh networks (like Amazon Sidewalk), and that they'll never include their own SIM cards.

Granted, none of this has happened yet... but when it happens, I'll start busting open my devices to disconnect any and all antennas.

I've recently read (in HN), that Samsung's appliances mesh network with other Samsung appliances with the hope of reaching the internet. So it's around the corner, it seems.

That's terrifying and I hope this isn't a default.

You already have to do it with cars, only a matter of time before these sorts of solutions start creeping in to other products.

Even if the "smart" features of a TV are rendered nonfunctional by not giving it a network connection, you're still stuck with a TV that takes a while to boot up (yes, really), and which may be built around a UI designed to navigate its smart features (like booting to a home screen instead of passing through HDMI input).

I've never seen a recent mid budged tv take longer than 4 seconds to boot

I have a Sceptre TV from a few years ago that takes about 15 seconds from power-on to even display a boot screen. It takes another 10 seconds or so after that to actually become usable.

Maybe it's just an outlier? It's certainly slow, though.

Mine cold boots in 15-20 seconds (I need to check that), and wakes up in less than four seconds if it's on. It's a 2020 model.

My TCL takes 2:40 to boot up. There is (or rather, used to be) a fast boot option, but it stopped working after the second firmware update.

Is it minutes or seconds?

My tb takes 40 seconds from click8ng power button untill even HDMI input works. The smart features take another minute.

It boggles my mind that anyone would connect a TV to the Internet (!)

Although it wouldn't surprise me at some point if Samsung or other makers started bundling cellular modems in or had deals to have them automatically log into the "free wifi" for the major cable internet providers :p

LG's app interface is good, my TCL just has Roku built in - why wouldn't I?

I'll agree on Samsung's end though. Everyone's Samsung TV I've ever tried has been stupidly laggy.

Not really, my Vizio has no connection to anything (firewall drops it's traffic, and it's on a separate VLAN). It takes 15 seconds to respond to input changes after waking it up.

I'm with you, but I wonder if this is the sort of "only people on this site care and the vast majority of the readership wouldn't use it" thing ... I'm not sure it is, but it could be, and I wonder if somebody with their ear to the ground/access to more analytics knows.

Look for digital signage displays and be prepared to pay double the price.

Not sure why you would care so much but this is pretty close:

https://www.rtings.com/tv/tests/ads-in-smart-tv