Every game has performance limitations. Personally I'm not enjoying more than about 120-150 engines very much. Frame rate becomes less and less tolerable.

Each map has mechanical limitations too: how many cities, how many resources, etc.. Once all resources are being consumed, this is close to "maxxed out." Strategy is only available in how to max out the map more quickly. After max is achieved there is a wait for many years at low frame rates to hit the target. This is the majority of playtime. I have hit this type of goal before, but without strategic considerations during the "maxxed out" phase it's difficult to love for regular plays.

I did start this, but only played till $200M or so. I made this comment because I have a feeling that such a large goal is discouraging other players from trying/completing your map as well. I feel there is often a lack of feedback on how players find a map. I'm quite curious how you are playing, how many engines at what frame rate?

idk maybe longer, depends on how much time you have to play. If you dont like to play that long then find something that more suited to your level of concentration and or satisfaction over time.

Why $1Bln net worth target. Is this meant to take a week to play?