It sounds like you still want a smart TV, just with control. Which is fine.
But for many people, we just want a monitor, maybe with speakers (I personally am fine also separating this).
I prefer separation of concerns — if I want to attach a computer to my TV, I’ll do that as a search device.
Why have a dependency on the TV hardware, when I can attach upgradable parts?
A monitor has a processor in it that is running an OS and software. These are digital devices. The nit you're picking is silly.
If you want to buy a bare LCD panel, they're cheap. But you're going to have to add a processor to it that runs an OS (which you're free to write yourself, along with the driver) in order for it to understand any input. All that slapped together is what we call a monitor, or a television.
If you want an analog television, they'll pay you to haul it off from wherever you see it, but you're going to have to add an external computer to it in order to process the digital information that you want to display into waveforms that you can push over coaxial cables.
Not wanting a "smart tv" means people don't want a smartphone for a television, an OS that they don't have any control over. If you want to make up another definition, you're going to have to set limits to acceptable RAM, clock speed, number of processors, and I don't know why you would waste your time doing that. The number, however, will never be zero for any of these things.
Because if you own a TV manufacturing company, you can sell more TVs if they have more features. You can get more features by including a linux SBC and integrating it. In fact, some of the paid-app makers will even _pay you_ for this "real estate". You could make a dumb-tv, but you wouldn't sell as many and you would have to charge more.
> But for many people, we just want a monitor,
> you can make it a PC and then turn it off
TV manufactories can get the best of both worlds: The people that want smart TVs, get a smart TV. The people that don't want a smart TV, can disable the smart TV features. Manufactors make one model and sell to both market segments.
Why should your preferences impose on the ones that don't want what you want? I guess the preferred way would be for manufactors to have add a feature where the tv prompts you if you want to enable smart features when you boot the tv for the first time, but it's a bit difficult when manufactors get more money when they have these features enabled by default.