Let's first see what wealth is?
To use the definition of economics: wealth is something of value.
What value is: Something that seems useful to the owner or the dominant.
Then the greatest wealth = the greatest value (both materially and spiritually), and the greatest wealth of a man is what seems to him to be the most valuable, meaningful, and useful.
Many people may think that material wealth is the most directly affecting value, such as: money, house, car, etc., but the definition of value at different stages will be different, and the demand for wealth will be different.
For example:
1. As a child, I like "mini special attack teams". However, fame, status, love, etc. are not valuable to children, at least he does not think it is valuable, may give him a "Ford, Max" can make him feel happy and cherish it, at this time the child thinks that "Ford" is his greatest wealth.
2. The wealth of the adult stage becomes money, status, wife, house, car, and many other things that he finds useful, and he works hard for what he does not get, desperately trying to get what he thinks is the greatest wealth, at this time adults feel that material and spiritual are the greatest wealth.
3. In old age, the body gradually ages, health has become the most useful and valuable thing he feels, he hopes that he can have a healthy body, not to be plagued by disease, at this time health is what he thinks is the greatest wealth!
Different stages can make him have different values and views on wealth. Having said that, it feels like the greatest wealth is having the least amount of stuff! In layman's terms: what he wants to have the most, no toys want toys, no money and no wife, want money to think of his wife, no health, want to be healthy! So to say that a man's greatest wealth is to have everything, to pursue everything, but to find that the greatest wealth is what has never been there.
The Buddha said that "the four great voids are empty", emptiness is nothingness, nothingness is nothingness, but what the Buddha pursued all his life was a "nothingness".