Its very funny that this is so talked about in America. I currently live in the Yucatan (where the Mayans lived and still do) and no one here gives it a second thought or even thinks it is worth talking about. I asked my girlfriend who has some Mayan blood and she said the calendar simply ended because the Spanish came took over dismantled most of the temples and pyramids to build catholic churches. Most of the population was wiped out due to influenza and war and simply work stopped on the calendars as the culture died.