[Lalaith]

What an interesting discussion!
If I might add a couple of observations - our own history shows us that city populations can rise and fall quite dramatically. Rome, at the peak of the empire, had one million inhabitants. So did Mexico City at the time of the Aztecs. But both cities dwindled to a fraction of this when their power waned. So too, Gondor could been a much more populous city in its prime, than it was at the time of the war of the ring.