Two things I haven't seen anyone else point out.

If you set P(ego|ent, sim) according to the fraction of entertainment simulations in which the person playing the game has an avatar in the game, then P(ego|ent, sim) > .99.

The most popular PC games ever are The Sims and The Sims 2. Then World of Warcraft which is a multiplayer game. Single player games with avatars do not make up 99% of the market, not even close. And that says nothing about the non-electronic games people play like sports and dating which are almost all multi-player.

We notice there are no immortal world leaders on Earth.

Quite a few have not died yet. One might infer from history that they will- but once you decide we're in an entertainment simulation that evidence is worth little- the simulation may have just begun. I suggest you seriously consider swearing allegiance to Kim Jong Il. Further, there is no particular reason to assume the player is any good at the game- perhaps she died without saving in 500 BCE.

In general the probabilities are really off and you haven't dealt with the issue of having extreme utilities for competing choices (should I choose Christianity or Islam or trying to extend my life and save the world?). But I upvoted because it is kind of interesting and not deserving of -7, though I predict it will go much lower than that.