That’s why increasing the limit by 10 would be much more expensive than building 1 house. I have suggested an initial cost of 200 (equivalent to 4 houses).
From then on, caravans are something very easy to raid, they are not like a villager who can be safe in the base producing resources, (or even prevent trade many times destroying the markets, etc…) and they are much less profitable than villagers producing resources too.
So I think this system (no-pop) wouldn’t be problematic for them.
200 Wood, or any other resource is not really an investment in the late game.
But even if it was expensive. Once you payed that you can keep those units around for “free” while every other unit takes up population.
It is a very strange decision to just make 1 unit cost no population.
I think there are more elegant solutions.
Trade routes don’t have to be long you can have short safe trade routes that give small amount of gold on a trip. Eco units should always cost pop.
200 + 250 +300 + 350 = 1100 resources. And you still must to create the caravans that can be raideable.
Could it be too much?.. I don’t know, maybe they should be more expensive, or stack fewer times, or give only 5 caravans per upgrade with a maximum of 25 instead of 50 per maximum number of stacks… I don’t know, I’m just saying that caravans in the current game cause a population problem.
This population problem can’t be bluntly addressed by giving 2 more houses, for example, because caravans start appearing in the mid-late game, and those 2 extra houses would affect the settlement fights in the early game
But couldn’t they just introduce technologies that increase the house limit by same amount you are proposing to make them increase the Caravan limit.
Just that more houses give you the flexibility to choose what to use your population on, and not just Caravans.
Maybe it could be done, but since in this case the destabilizing factor is the caravans, I’m not sure if trying to address the problem in such an indirect way could cause other areas of game balance to be affected.
Something like a player who reaches the fourth age and still doesn’t need caravans could benefit from this increase in houses that would be intended for caravans, etc…