It's just a darn calendar. Chinese whom are in the year 3000 and something could easily predict the end of the world in year 4000, which is so many years away from our Caesarian calendar. Yes the Mayans had a very nifty calendar and they where among the first to seriously study astrology but they didn't have massive telescope like we do now. How in the world a little group of people can so easily predict the end of the world from an archaic calendar.
Mayan Calendar isn't wrong at all, it was just the end of a cycle, when Playboy stopped publishing their calendar, was it the end of porn?