[Gregstrom]

The game is in fact extremely realistic - it's just that no-one ever noticed that all units in the game are members of the New Amalgamated Union of Gribblies, Humanoids, Thugs and Yetis (NAUGHTY). Among the NAUGHTY Articles are extremely strict rules on the duration of melee activities any NAUGHTY Member takes part in over any given month. The NAUGHTY rules specify exactly how long the attacking and defending sides can stay involved in combat, and punishment for breaching said rules is carried out on the spot. This is why attacking armies leave so promptly - they're actually going off for the union-mandated tea break.

Pretenders beware - argue with the unions and the NAUGHTY people will come and get you!