I believe the Roku TVs can operate in a fully functional "dumb" mode if you don't connect them to Wifi. I'm guessing that applies to some other brands as well.
Nah -- Rokus are really bad here, they want to run roku first then be a TV. The more traditional brands -- LGs and Samsungs of the world -- do better at this and don't bitch as much.
My (older) Samsung TV works the same way. I haven't seen a TV that refuses to operate without an internet connection yet.