Suggestion: Use old game's world and end state as basis for new game

[Sitoutumaton]

Looking down on a multiplayer game that's slowly crawling to its end after some maybe gigatonnes total worth of nuclear weapons thrown about between four players, it's given me the following idea: (apologies if presented already prior)

Start a new scenario based on an old save file's world, same geography, remaining unmined resources retained, existing cities turned into ruins or retained as starting cities for new minors and majors and world population spread about. Granted, it would leave for more lower tech overall with most finite resources expended by prior civilizations.