Is it realistic to aspite to create your own multiplayer video game with the only goal being to spend most of your time in that game? I want to evade reality in a world which would be better for me.

Let's assume that you have a rather big programming experience, and can work on the game all day long. Let's also assume that the idea is interesting enough for a few other people to work with you on this game - it's basically a game which was rather popular a decade or so ago; but is now dead since it was never updated to better graphics and performance.