"... we have a detailed simulation running 20 million AI on a server that communicates with game servers and our solar system servers ..."
That WAS all well'n good UNTIL the development of procedurally generated planets. Specifically, cities that will be a type of terrain just as are the rocks and trees to which we have become accustomed. These cities will have to be animated.
I'm thinking of Earth. Earth is one big city.
Earth animation will be far more dense with NPCs than that of Space. In Space just a few ships or NPCs have to be instantiated if a contact has been made. On Earth, there will be near constant contacts.
The number of NPC count must now be viewed differently. Yes, probability of bumping into space-faring NPCs will remain 10:1 structured and based on various factors such as distances, economy and populations. But bumping into land-based NPCs, in some places, will be near 100% and constant.
What I'm getting at is that planet-side, node-based traffic must also be emulated. This has never been mentioned by CR and CIG. This is required in order to establish logical and likely encounters of trade, bandits, vehicles, etc. Just as it is in space. No random pop-ups as in most games.
CIGs planetary placeholders in the economic system (ie Earth has a trillion people) must be modelled in more detail. Nodes, for example, must be estimated on a per square kilometre basis.
I'm thinking the NPC to PC ratio will be closer to 10,000 : 1. And by my math that is 20 billion AI NPCs. I'm pretty sure they are developing a new instancing technology to do it, too.