It has been several times. The answer is: technically it´s possible, but it doesn´t make sense. The UI of the game has to be adopted for TV usage due to the (in average) much bigger distance to the screen - otherwise you can´t see ****, I tried it with Diablo 3.
Regarding Steam Big Picture Mode: isn´t that just an adjustment for the Steam UI, or does it change also the UI ingame? That's what's important, and I doubt that many developers would like to optimize the game UI for two different environments (PC screen and TV). But if they would do that, that could be an option for satifying many.
It's only for the steam ui, but technically you wouldn't need to use it anyway since you'd be using a keyboard/mouse regardless, the size of the fonts and ui would of course be a bit skewed. But I mostly meant it as a response to the OP who was saying that they should release it on the ps4 since it supports mice/keyboards, I just don't understand why you need a separate version to be able to play it on a tv while sitting on your couch when a long hdmi cable would do exactly that.
