TVs, especially big ones are MUCH more expensive than PCs. A good TV should last for years, maybe more than a decade. Just like a PC, I would think that the "smart" in "smart TV" will change radically every six months. Would you really want to, say, replace an $4,000 85" TV every 2 years because you couldn't add enough RAM or a faster processor, or an entire "smart module"? Can a smart TV do anything that a "dumb" TV + HTPC or media player can't do a lot better? I'd much rather upgrade an HTPC or replace a media player every few years.
Do you know what an OLED TV is?
CNET explains how OLED technology differs from regular TVs, and what you need to know to make the right shopping decision.