If I have understood it correctly, after some point this game becomes too much of a chore...
If there were a natural limit (something like diminishing returns) based on the number of planets you had...
Can god make a boulder that is so large that even he can't lift it? The game only becomes a chore if you've built a larger empire than you care to manage. I think there's a few players who maybe have some sort of OCD complex. Anyway, the moment you arrive at this point of feeling like its a chore, you should stop expanding, because you've reached the "big enough" state.
The other part of this is that there are several techniques for optimizing how you run your empire. Not every colony needs to be checked every turn once you've reached a certain size/colony age. Some players use Mind Control to avoid having colonies that run out of food/hydrocarbons. A mind controlled colony needs very little maintenance.
People that want to try to manage larger empires should be allowed to. The problem is the players that don't seem to be able to stop themselves from continually expanding even after they've reached the "big enough" point. (looking at you Amazoneon)
By the way, from the looks of it, "hydrocarbons" are the only resource that in due time vanish completely. Does that mean that after awhile, the heavily colonized areas become essentially uninhabitable and worthless, forcing migration to yet undiscovered places?
A colony with the Drilling Planetary upgrade enabled never runs out of hydrocarbons.
