D00d! You think those statistics are crazy? Welcome to The Elder Scrolls series! As Freddo the Mod pointed out, there are people who are die-hard fans but have never finished the main quests or take years to finish them. Would you believe, I played Daggerfall and Morrowind for a billion hours each (slight exageration...) and never finished their main quest? Oblivion is the only TES game I ever completed, and I still never did all the guild/side quest lines. Arena, I may or may not have finished, but I did get pretty far (I think my HD had crashed

).
The games were originally designed so you could have an entirely new experience with each playthrough, and some people spent more time planning out and making new characters than actually playing the game.

Some people get into modding and don't really actually play the game much, but just get enjoyment from the creation process. You can thank those people for constantly making cool stuff for your favorite TES games. Just wait, the Skyrim mods are just getting started...