This was surely written by someone who has enough money that all their needs are covered.

Studies have shown (and anectdotal evidence from my own life corroborates) that if you can pay all your bills each month/year without worry, you will be happy. Above that the additional income is nice, but won't make you appreciably happier.

The "break-even happiness" income in the US is around $75,000 /year (a few years ago at this point in 2023).