OK, maybe you missed the point. By punishing rapid & thoughtless expansionism in the late-game, Maintenance is a means of curing bogging down in the end-game. Now, if the need to conquer the entire world was entirely eliminated from the victory conditions (in favor of merely dominating the other players) then the problem would be entirely solved. For my part, I never ran into major issues with Maintenance in the late game, because I almost always pursued a diplomatic, space race or cultural victory. Aussie.