What made people believe that a larger number of money assets equals prosperity.

I think it is a natural extension of evolutionary imperatives - unfortunately on our planet at least (as far as we know) there is no other life-form that has gained the ability to dominate the planet and consume resources to the same degree.

The natural survival enhancing benefits of this belief now has a detrimental effect not just upon ourselves but also everything around us.

You sum up the problem well here:

In today's society, we no longer use what we need. We live with excess.