You can easily get overwhelmed even if you stick to a few genres or platforms. I own Fallout 3, Dragon Age and Mass Effect 2, and I am pretty confident that I will not come close to fully exploring them before the next great RPG is released.
I think that's part of the experience, though. Having just finished Mass Effect 2, I can tell with certainty that there's a huge amount of the game I never got to see due to my choices, but I'm fine with that. One of the chief strengths of that game is its ability to give every player a unique experience - you don't need to experience every line of dialogue, every possible outcome of a situation, etc etc, to have a profoundly enjoyable experience.
Even if you just focused on a single game like World of Warcraft, there is enough content and stuff to do that you would probably use up all your leisure time.
I have a monstrous backlog of games I feel I should play, sitting right next to the pile of books I should read and movies I should watch. Sadly, I have accepted the fact that I will never be able to get through them all.
In all serious though, if you want to truly get into the endgame of WoW, you generally don't have alot of time for other games (this is of course depending on how much time you have for gaming in general). Blizzard has definitely made it easy to spend the majority of that time in their world.
(Yes, FF may not be to $COMMENT_READER's personal taste, but you know what I mean.)