It's worth remembering that whilst BattleMaster is a game set in the middle ages, it is not a simulator. If we started adding in realistic middle-ages life expectancies, diseases etc. this game would not be as much fun. We can already see from instances of rapacious looting that a realm recovering from massive depopulation and death is not something that adds a lot of enjoyment to the BattleMaster experience. It's nice to know what life expectancy in the middle ages was like, but we shouldn't take too much from it.