Point of clarifiction, guns are a medievl weapon, they were present in small numbers at the battle of agincourt, as well as others.
It takes a very long time for the gun to be a more effective weapon than the bow or crossbow, the major benefit of them was the lack of training involved to use them, that is why they over took other weapons. They were only effective in large numbers becuse they had rubbish accuracy. A bow could be shot further and faster and with better accuracy, as could a crossbow, they just required far more physical training/fitness than a gun. So simply because guns are available, it does not automatically make them the better option. So many nations with a long legacy of certain skills and tactics, may stick with their preferred weapons.