Most of the people who could afford/had access to TWC also bought TAD, or disliked the expansion enough that they had no interest in buying TAD.
Vanilla is still very popular, TWC/TAD is very popular. TAD alone is a growing group of players who you'll see on the TAD server. TWC only - hardly any of those folks still play on the TWC server, most have ditched the TWC and reverted to plain vanilla AOE3 where the majority of players are.
One of the reasons there are more Vanilla players is because in some parts of the world, the release for TWC was delayed by up to a year (!) and people either lost interest in the game itself, or just waited another three months for TAD.
Crunkatog on ESO
Bart331 balance suggestion: aztec: remove civ
Voltiguer: Ender, Sioux in 1.04 will be a top civ, no matter how many layers of Sioux goggles you put on
schildpad on Elephants: ...their mansabdar unit sucks so hard it looks like a black hole
Crunkatog on Steam.[This message has been edited by As_Saffah (edited 02-20-2010 @ 04:53 PM).]