Water supply is usually not excessively hard. 1 Water mine should produce so much, you can often reduce the production to 25%, run your Farms and still sell excess.
Frozen plains actually act as unlimited place for mining.
In places where you can collect Rainfall or have sufrace waters (Rivers, Lakes, Seas) that can actually fully cover your consumption. We are talking about free water in the
thousands. On the right planet water is such a non-issue, it becomnes worthless to sell.
So the 3 cases for Water are:
- Such a non-issue, it stops having any value for selling
- Need a mine, but unlimited reserves under said mine
- need a mine and limited reserves per mine. Need later techs or some expansion to maintain supply longterm
Food
- Dome Farms are the most reliable food source. You can put them
anywhere. You can even put them into the fields of Open Air Farms. Main downside is that they cost some energy.
- Open Air Farms are very inefficient with water - but the advantage is that they need no upkeep besides workers and water. If you can use them, there is a 99% chance you got water to spare so you can run them no questions asked. Temperature variance can still be an issue however.
- Hydroponics are hella expensive to build and maintain - except for water upkeep, there they are peerless. You can also put them into a city that already has a farming asset so a trivial upgrade
Manpower
The main issue with Manpower is geetting enough of it out of your city, without runing their growth. And keeping losses below the Casualty Tresholds. Long term you want to keep recruitment < growth. But early on you get so much growth from migrating free folk, the 500 start is not a issue.
The Real issues early games are:
- Metal
- IP to convert those metals into something usefull
- Machines to build most buildings
Even water and food are only a temnporary drain of those 3, if that much.
Are my only true long-term threats the major powers? I assume minor powers and below are merely nuisances since they only ever have infantry and will be outclassed given any tech breakthroughs?
Mostly, but not entirely.
Minor Militias do improove in quality over time. And especially Natives can have some pretty crazy guns of their own design. Nothing Infantry with Automatic Rifles or Gas Powered Small arms and Combat armor or light tanks can not deal with - but there is some decent stuff.
Minors with a city are valuable to attack - because they have a lot of the population, but the others should be avoided unless you need to get through their territory.