It's not fun to capture a city on 300-350 turn and then spend 50 turns, only to restore its production and scientific capacities, defensive potential, even buying every building that requires more than 1 turn for buildings. Especially in the case of capturing city-states - it takes a lot of turns to raise a city to a good level.
For example, 10 buildings cannot be restored faster than in 10 turns, since each building will take at least 1 turn to build. And if there are 30 such buildings, and some require 2-3 turns even with the cost of gold, then 25% -33% of the remaining game time (500 moves, capture at 300-350) we just restore the city instead of producing armies, aircraft and fleet.
Defensive and military buildings, monuments (what else?) are always destroyed. These are already about 10 buildings that definitely need to be restored.
In vanilla, it was possible to quickly rebuild a captured city simply by buying up all the destroyed buildings, but this required having a good economy.
For example, 10 buildings cannot be restored faster than in 10 turns, since each building will take at least 1 turn to build. And if there are 30 such buildings, and some require 2-3 turns even with the cost of gold, then 25% -33% of the remaining game time (500 moves, capture at 300-350) we just restore the city instead of producing armies, aircraft and fleet.
Defensive and military buildings, monuments (what else?) are always destroyed. These are already about 10 buildings that definitely need to be restored.
In vanilla, it was possible to quickly rebuild a captured city simply by buying up all the destroyed buildings, but this required having a good economy.