You are conflating two totally separate factors: the number of units and the number of map plots.
Like I said (and probably not the first time) - I'm playing in such a way that there are NO "40 other civs" on the map, because I wipe them off soon enough.
On the other hand, I do like building tons of MY cities, though that hardly raises a number of units, because I usually have just one per city.
In fact, I think my cities take up (and that's the idea) more unit-producing map space from barbs and animals, than the number of units I produce instead of them.
So the map-total number of units is actually LOWER this way.
But on the other hand, I still didn't find out whether the map's SIZE itself affects the memory or the end-turns.
Not how CROWDED it would get overtime - but the map plots themselves, maybe some per-turn calculations or something.
So,
@raxo2222, can you please explain that part explicitly - what is the effect of the map size ITSELF, regardless of what's ON the map?
Let's say it's an empty map with just one city on it (which I had played in the past as well) - so would the map size affect the game play, and how/why?
Thanks.