I like multiplayer a lot. But in turn based games, I'm going to end up playing it single player. I haven't played Civ IV multiplayer since I first got it and that was just to try it out really.
GalCiv II as a single player game: $39.95
GalCiv II as a multiplayer also game: $49.95.
We made the decision that the 95% of users shouldn't have to subsidize the 5% of players who want multiplayer.
All our other games have multiplayer. That fact seems to get lost. Heck, Stellar Frontier -- 1997, one of the first "MMO" type games ever. Trials of Battle -- 1996, one of the first FPS's that allowed dynamic adding and leaving (pre-Quake era). Those were in our OS/2 days so few people have heard of them.
Our next title, The Political Machine 2008 is multiplayer. We have another strategy game due out in 2009 which is multiplayer. Society, which isn't going to be out any time soon but is in development is multiplayer. And odds are, a future GalCiv sequel would have multiplayer but only because the player base of GalCiv has gotten large enough to justify it.
It's ultimately a cut and dry business decision. GalCiv I sold around 75,000 full-priced units and an equal # of discounted price units. IF let's say 5% (and that's being generous) of the market would choose to purchase it because it had multiplayer (and let's be clear - a major feature has to be able to justify its cost in being able to put a user over the edge of the purchase/no-purchase decision for it to be worth it).
But for the sake of argument, let's say that feature would have added an additional 10% to the market. For GalCiv I, that would only be 7,500 units. Not remotely worth it. GalCiv II is likely to do double that so that's 15,000 units. By GalCiv III you could be looking at 20,000 units more being purchased because of that. At that point, it starts to make sense.
Multiplayer could show up as a feature of a future expansion pack as well. It really depends on how well Dark Avatar does (in the sense that we have to see how much demand there are for expansion packs and what % of the GalCiv II audience we can reach).