What good are colonies? By colonies here I mean those with large populations.
I built some colonies on the assumption that they are a good thing to have in any space 4X game. Now they are big enough (~50m pop each I think) and growing at a high enough rate (~10%?) that they are consuming a large and ever growing amount of my HW's production and D* stock just supplying them with infrastructure so they don't run short of housing and get annoyed. One has enough D* potential/production that if I hauled enough industry there it could probably build its own infrastructure, but its D* supply won't last forever and one of the reasons I built the colony there in the first place was a plan that it could mine D* and ship it to the HW. I can foresee this infrastructure problem growing as the colonies continue to grow.
I can see the value of colonies to man mines which are cheaper than automated mines to produce. Also, once the HW resources are mined out, the existing mines are useless there but can function on colonies that have resources to mine. Of course eventually those colonies resources will also be mined out and the process would have to be repeated at a new colony site. Assuming of course that you are lucky enough to find an inhabitable world that also has decent mineral resources. But then what do you do with the original colonies that keep demanding more and more infrastructure? Let them go in to revolt?
Traditionally colonies ship raw materials back to the homeland to feed industry there. As the colonies mature, they develop their own industry and eventually end up trading with the homeland (or rebelling of course and going their own way).
Aside of manning mines, the only real advantage I see to pop on colonies vs leaving the pop on the HW is the growth rate on colonies seems to be higher. Should I reverse my colony ships and start siphoning off pop to return to the HW to grow the tax base? I would of course be fighting against the efforts of the civilian colony ships. I can think of a bunch of small uses for colonies but I'm asking about the big picture here. I tried adding research centers to colonies so I could research more than one technology at a time, but I see little real benefit to that vs just researching one thing at a time on the HW faster.
