Because together, they define your PPs/turn and hence how fast you can produce warships. In late game (where more balance problems can happen), total population is the most crucial meter to define victory, very close to industry boost from species. Also, this means wide vs tall is not very funny (if you go tall). This means game is decided in the beginning (and by alliances): the one that manages to get ahead on espansion and do not neglect military will win most of the time (we are not comparing AI vs human here).
Therefore, if you are bigger than someone else, that someone else will have very little chances to win you in the growth race.
That is, the bigger you are, the faster you can grow. because you need to take out an enemy).That is, IMO, the deepest root of the problem: the exponential growth of everything implicit in a 4x game. This stops if expansion cost increases (e.g. Ophiuchus wrote: ↑ Sun 8:17 pmIn the expansion phase basically doubling the number of planets in your empire leads to doubling the resources, which leads to you doubling the number of planets again in half the time.
