When people start affording more with larger incomes, their assets turn into overhead that must be managed. It's a cliche, but the TCO of most things is more than their face value. On the other hand of that, there is an amount of dollars one can earn to build a framework and make their money be self-supporting. I.e. the returns on investment covers taxes and expenses and actually has non-negative growth.

While I agree that contentment is /a/ key to happiness, it won't exactly motivate you to strive for things completely out of reach. Just the chase of your goals can result in happiness.