The Calendar Ends Because It Has To?

I just read this blog post that was submitted here as a comment:
http://shanmadham.blogspot.com/2008_02_01_archive.html

I'm not a fan of his main theory:
As Solar Sun aligns with the galatical center in 2012, the electro magnetic gravitational forces balances out only after massive Solar flaring of huge Mass Energy ejection leading to creation of tiny planet between Sun and Mercury.

But then he proceeds to make a very valid point:
"Around the Sun in 365.2425 days" by Earth will change and we have to revolve longer to curcumscribe our Solar Sun. Perhaps this is too a reason why Mayan/Aztec's calenders end on 21 dec 2012 and they didnt calculate Calendrical system/Time after Time Wave Zero in 2012.

If there was to be a pole shift, or some kind of disturbance within the Solar System, then the Long Count calendar, which the ancient Mayans used for such things as predicting eclipses, would no longer be accurate. Even if our day was suddenly only 2 minutes longer, or if the orbit of our moon was affected, the calendar would lose its accuracy!

So I'm thinking that current calendar ends on the winter solstice, not because of a catastrophe that will happen precisely at 11:11 GMT (they weren't that clever), but because that is the final important event that the calendar can accurately predict.

The event that changes how we see the sky will happen sometime between Dec 21 2012, and the next important event they would keep track of. That event would most likely be an eclipse, an equinox, or a solstice.

The next solar eclipse is May 10, 2013
The next lunar eclipse is April 25, 2013
The next solstice or equinox is Mar 20 2013 (at the time of 11:02 UT)

That's my verdict - "it" won't happen on Dec 21 2012. It will happen some time between that date and Mar 20 2013.