Um, I can't answer for the team, but I'll give a plausible answer: they'll keep working on the M2TW engine.
First, the day of MW2 is not yet finished. Look at the other TW games, RTW, MTW and even STW! Plenty of people play those. And think of the folks who won't be able to play E:TW because of technical issues? They'll stay with the other games of the series.
Secondly, E:TW is a new engine, which means modding it will start slow, since we'll probably have to learn the intricacies of the new engine. They say 10 playable factions, but can we enable the 40 others? We don't know, and that's just one example.
Bookmarks