Some do that. CNET writes at http://www.cnet.com/news/20-tvs-tested-which-sets-can-pass-surround-sound-to-a-sound-bar/ Of course you can figure out that you can have other than a sound bar.
Bob
We purchased a Denon AVR1613 Receiver and thought it had Coax input, we were wrong. We have a cabin in the mountains and they do not provide or offer cable boxes, I've called and asked, nope.
Since the Denon does NOT have coax input, what do I use to convert the Coax Cable to HDMI so I can utilize the speaker system when watching TV?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic