Because have lots of money gives you the economic power to survive adversity, pursue interests that are more fulfilling, do more good in the world, etc...
I think what TheOtherHobbes means is you can survive adversity and pursue fulfilling interests without rising to the level of 'rich' - unless your interest is something like having colleges name buildings after you!
Indeed, it would be a poor reflection on our society if you had to be in the top percentile for income to merely be economically secure.
