>>64081906 (OP)
because all over the world except in countries with conscription the number of volunteer is decreasing, so we need to ensure the soldier need to stay alive as long as possible, that mean body armor, better helmet, uniforms with more pockets so he can carry more stuff and made with better materials, a fuck huge backpack to carry all the other shit he need to survive on the field ( that will also destroy his spine once he reach 35 years old ) and also his rifle with an other shitload of ammo for it to make sure he can keep shooting as long as possible.
basically in your OP the average life expenctancy of the soldier during a firefight was 1 minute maximum, with all the new stuff we have today we raised it to 3 minutes maximum, result in both case can vary depending on soldier training and exposure to enemy artillery/air support/vehicle support