One of the main reasons the ECW December to Dismember didn’t have a larger advertised undercard was because Vince McMahon reportedly wanted all of the viewers’ focus on the Extreme Elimination Chamber main event.
McMahon was said to have been even against advertising the “open challenge match” between The Hardys and MNM. It should also be noted that McMahon may take this new philosophy (while not as severe for the ECW PPV) for upcoming Raw and Smackdown PPV events by announcing two to three matches only and downplaying any undercard matches, if even announcing them ahead of time at all.