Someone raised an interesting point here, albeit unintentionally, so I won't give them credit.
We actually have basically no context for how far in the future the Avatar is, do we? I don't remember any flavor text giving away how many years/decades/centuries/millenia/etc... have passed since ATLA or Korra, except some geographic/city details that confirm it's post Korra (which we already know).
I wonder if it's gonna turn out that the Avatar MC is actually only 1-2 generations removed from Korra, and because of her losing the spiritual connection to past Avatars, that's why current Avatar is a shitter who sits around his house playing games and fapping instead of solving world problem. Yeah, it's implied things aren't terrible in his time anyway, but still - what if losing the connection to the Avatars who put their lives on the line are why he is the way he is?
I'm guessing he just has a serious case of the shitter mentality at the beginning of the game (or Rance mentality through the entire Slave Route, which is even shitter), but still. Would be interesting if there's some explanation or timeline given. Technically if he's in the Republic City most nations have reps there, and the next Avatar should be from the Earth Kingdom, so he could theoretically be as soon as the next Avatar after Korra.