I really wish TV mfgs still offered dumb TVs, even for like $20 less. The features on the many I've played with (access to a lab with hundreds of smart TVs) range from "unbearable delay changing the volume + UI crashes randomly trying to switch set off" (yes this seriously happens on a newer production Samsung with the little click stick selector on the back as the ONLY physical button; turning it off requires clicking then scrolling to "power" and clicking again) to "noticeably slower but not unbearable when changing volume".
I really preferred my TVs to be as dumb and as responsive as possible, but I know that many people won't buy a dongle for the "smart" functionality of their TV has it built in, even if the experience is awful, upgrades are few and far between, support ends after a year, and the internals powering the smartness are non-upgradeable low-to-midrange smartphone boards on their new >$1000 set. Also, getting a >$10,000 TV doesn't get you much better software or much better smart guts, which surprised me at first, but I guess it makes sense; they're not going to spend millions in R&D for the products that sell in small numbers.
I bought my first "smart" tv last year, made by Sony. When it works, it's a great tv but every now and then an app will temporarily lock up and you have to wait 10-15 seconds for the tv to come back to life. Or other times it locks up entirely and I need to manually power cycle it. It's an Android TV.
I do enjoy some of the app integration (hulu, netflix, amazon), but at this point, I'd rather have a stable tv and use a roku instead.
They sort of do - look for "commercial signage" displays. Prices are similar to consumer models, and the "smart" crap is either removed outright or greatly reduced (I saw a number of versions with built in slideshow functions, but that's about it)
$35 is about the right amount of money a smart TV enabler.