The irony is that you can still buy just a good screen with good connectivity options and basic controls, but the market is advertised as "display screens" intended for things like advertising or video walls.

I don't understand why the same manufacturers/distributors offering these products don't also pitch them as TVs with well-defined specs and no junk, probably with some sort of "expert"/"pro" branding that makes them look like a high-end choice.

You could pitch one of those, a basic 2.1 home sound system or the like, and maybe a small control/switching box that everything plugs into and that also accepts your source feeds, and you've got a mini home-theatre-style arrangement that could be quite attractive to those who value decent gear but don't have the budget and/or space for a full home theatre setup that would cost at least 2-3x as much for entry-level equipment.

> The irony is that you can still buy just a good screen with good connectivity options and basic controls, but the market is advertised as "display screens" intended for things like advertising or video walls.

That used to be an obvious possibility, but recent products in this category tend to run variants of Android/Tizen/webOS complete with Wi-Fi to support remote management. There are still a few relatively "dumb" models of commercial displays out there, but they seem to be a dying breed.

Because only two manufacturers make large OLED screens and maybe three make advanced LED screens and they are all massive conglomerates that control the market.

I suppose my implied question here is why control the market in that way even if they do have the practical ability to do so? If there is a market for simple, good quality products and people willing to pay a fair price for them, why would you exclude it, particularly in favour of a market where more of your revenue comes from dubious sources that could backfire in terms of PR and/or be less reliable in terms of future potential earnings?

What about not simply enabling wifi connection on the tv? My few year old sony tv is the dumbest possible secondary pc monitor, with great screen quality. I couldn't care less about any of those apps, I have vastly superior PC for those if needed.

This is a dangerous argument to rely on, because it still allows for devices to phone home via independent means. Just as your new car may well have some sort of embedded mobile network access today, so your TV may come with a built-in SIM, or use some kind of mesh network that doesn't rely on your own home WiFi access.

The problem is the principle that it's OK for your devices to monitor you at all without your explicit knowledge and consent -- or even with those things, if the market leaves no reasonable alternative and so the consent isn't really consent at all.