It's also because in an advanced economy, the older folks are busy with production, which funds the war. In less advanced economies, maybe not so much, but thos

It's also because in an advanced economy, the older folks are busy with production, which funds the war. In less advanced economies, maybe not so much, but those economies also have an earlier transition to general purpose adulthood including employment and parenting. Also, children are quicker to replace. It takes only 12 years to produce a 12 year old soldier, and war-torn countries tend to have a skewed age distribution.