The issue is that most people seem to leverage their money to the hilt. They earn $10,000 more, they spend ~$10,000 more. I can see money making you less happy in that situation, because you now face more downside risk if the money goes away.
Whereas if you earn $10,000 and only spend $0-$1,000 more, then you have options, including the option to not do anything to earn money at some point in the future.
The above is a version of the Mustachian philosophy, but you don't need to cut spending to a bare minimum to pursue time. Nassim Taleb argues for "fuck you money", and has written skeptically of the "money doesn't lead to happiness" idea. For him, self-ownership and independence of money is the key. The main purpose of money is not to spend most of it, to have a reserve.
People often ask how my business is going by asking if it keeps me "busy". They're using the wrong metrics.