This natural instinct is augmented by the fear of being on our own. Sexual instincts figure into this as well. Children are fragile, vulnerable, to have a lot of resources available is very attractive to reproductive instincts. Money fits all these fears of not having enough for the future. It is very difficult to store food, fuel, material resources.
Money gives the illusion of having great resources on hand.
In fact, unless the actual resources are there, the money is nothing. Some people know that, but they like illusions. And it does work for short periods. Balance of energy says we should not use resources faster than they renew, whether trees, animals, soil, oil, coal, breakdown of waste, etc. This can be figured on an objective basis, one piece of the planet at a time.