At the end of WW2 in 1945, the weapons manufacturers in first-world countries realized the vast profits to be made from weapons sales, but in order to sell more guns and ammo requires use and destruction of equipment, and that requires WAR!
When a weapon producer invest years and millions in research and development of mass slaughtering tools, they need a ready market to recover the costs and then turn a massive profit and therefore they have subtle ways of getting countries to be at war, and they truly do not care about the thousands of lives being destroyed. It's only about getting richer. It's the same reason America must maintain the ancient 2n amendment and allow even 12 year olds to carry guns legally.
The billions spent on weaponry by governments around the world are all tax payers money and that money just goes into the pockets of the already wealthy fascist minded folks, while the masses struggle to stay alive, infrastructure is falling apart and education costs are excessive. Humans, primarily of the male specie, prefer to spend trillions on making better ways too kill humans than to develop better ways to make life better for all.
Greed is the demon within.