You are right in saying no TV is "retina display" with regards to the number of pixels per inch (ppi). But keep this in mind. The retina display makes a lot of sense in a device that's 9"-15" from your face because the visual perseption of the pixels almost completely disappears. But when you have a display that on average 10'-12' away from your face, the pixels are so small that's it's a huge waste. Not to mention TV is showing no signs of increasing the resolution to greater than 1080p anytime in the near future so again all those extra pixels go to waste. And furthermore, a display that's 200-300ppi at this time would probably be many times the cost of the new iPad. And that's not a competitive price in any economy.
Here's the numbers:
True HD= 1920x1080 @16:9 aspect
iPhone =960x640 @ 4:3 aspect
iPad=2048x1536 @ 4:3 aspect
True HD translated into 4:3 = 1920x1440, not that far off from the iPad.
Pixels might be bigger on an HDTV but are very close to the same proportional ppi when viewed at normal distances.