I had fun watching Dynamite, but I guess the ratings disappointed. From some articles linked in a bloodyelbow article:
Quietly, the ratings number came out for the 2010 K-1 Dynamite show on Tokyo Broadcasting System and it was a 9.8% rating. A sub-10% rating was the very last thing K-1 needed. (Though it was nice to know that they ended up giving an attendance for the show - 26,729.)
The first part of K-1 Dynamite: The Power of Courage 2010 aired from 9:00 p.m. to 10:50 p.m. and pulled an average of 9.8, while the second half ran from 10:50 p.m. to 11:39 p.m. and drew a 7.8 score. Both numbers fell short of the ratings for “Dynamite 2009,” which aired on TBS in three parts and scored averages of 16.7, 11.8 and 10.6.
Some of the articles quoted in the link also speculate that they'll lose their current TV deal. But on the bright side, they indicate they might have a station to go to should that happen.