And yet, in all the polls that Stardock has ran about "would you use MP?" the response has always been less then 10% yes.
Indeed, before work began on GC2 or Altarian Prophecy, Brad (Owner of StarDock, and Lead Designer of GC) ran a poll asking if they should make an MP expansion for GC1, the survey results were very small "Yes" (around 10%, IIRC). When GC2's development started another poll was ran on what features should be included in the game, and MP got only about 5% of the votes.
Now, if you could find 25,000 people that play TBS games and would *buy*/pre-order a GC expansion that included MP, I bet Brad and his people would be happy to include MP. Heck, back during GC1, he said if only 10,000 people were willing to pre-order a MP expansion, they'd make it. But they never got more then 100 offers to pre-order such a thing, AIR.
If there was a real demand for a MP GC, StarDock would be happy to make a profit off that demad. But it just isn't there at this time. Maybe after GC2 is a break away smash hit though.