Stated by Frogboy
This is, by no means, set in stone but only our current plan:
When GalCiv III is finished (next year) its list price will be $49.95.
We expect to release new DLC for it every month for the first couple months and then once a quarter there after. Each DLC will likely be priced at $4.99. I'd expect there to be around 5 DLC released per year.
We also expect to release approximately 3 or 4 major expansions over the next several years for it. This is the main reason we went with 64-bit with GalCiv III -- we can keep enhancing it and improving it for many years because the underlying tech should be expandable for a long time. Those expansions will probably be $20 each.
The lifecycle of GalCiv III should be approximately 7 years (GalCiv II was released in 2006 and its lifecycle was about 4 years, we couldn't do more with it because we ran up against the 2GB 32bit game memory limit).
So basically 7 years of expansions and DLC.
Ideas that have been mentioned for expansions and DLC:
-commanders, place them in charge of ships, as they level up they can command fleets, and agents, return of espionage
-Snathi as major civilization, with their own tech tree, ship style and a mini-campaign.
It was mentioned in a stream once that they planed to have 16 major civilizations playable by the end of the game's development cycle.