Re: Why are there only two cities in the future? (spoilers)
Because all of the other cities were destroyed by the damned dirty apes.
Apes? Yeah. A Star Trek film is not without flaws until I can complain about the lack of Bonobo officers!
But if you pardon my casual pithecophobia, with Starfleet admirals being intimate with Section 31, I'd say Starfleet's primary locations is where
the damned dirty apes raged, making every other place a refreshing departure from the tentacles of this criminal organisation. Section 31's shenanigans are not taken well in future Islamabad, trust me.
R.I.P. Admiral James T. Kirk (2233-2267, 1969, 2267, 1930, 2267-2268, 1968, 2268-2269, Serpeidon Middle Ages, 2269, 2237, 2269-2286, 1986, 2286-2293, 2371)