I think it varies among people. Every study is different due to many different criteria just like a home inspection, two inspector will have two different results on the same home. I know people with money and people without money and they both have many regrets. IMO, money never really buy true happiness instead it buys you luxuries. You will never be happy because the more one has the more one wants and money can only buy things to certain point. Being rich create insecurity. If you are rich base on a salary working for someone you will be working all the time and will miss out on a lot of things in life. Rich people are still human and still feel sadness, pain, etc. so instead of feeling some of the struggles poor people have, they inherit other struggles that comes with having money. For example like having a car. Insurance, car tab, maintenance comes with it. Having money is the same, certain things comes with it, its part of it and you can’t shake it, you can’t have one without the other.
Look at Hollywood today, there are millionaire everywhere and some of their struggles are never ending. My manager at my last job who make twice as much always complaining that he’s broke and drive the crappiest car out of the rest and I’m trying to get to where he is? No thank you I’m more happier making less, less headache, less responsibility and its enough for the family. When the last time you got a raise and you celebrate then months later you feel the same like you still can’t save money and you need another raise. The more one has the more one wants and always feeling insecure, the list goes on…Millionaires no different.
I believe happiness is having enough money “txaus noj, txaus haus”. MOST importantly having a loving family, spouse, children, etc. IMO, the real TRUE Happiness is how you share yourself to the world. On your dying bed nothing matters, not money, not how big your house is, not how many places you’ve been to, etc, INSTEAD a self-evaluation of your walks of life and how righteous you were to the world, THE FEEL GOOD ABOUT YOURSELF, you know. This will determine your true happiness before your last breath.