What about health problems? Stress? Happiness? Money can only go so far to alleviate problems in these and other areas. When it comes to the biggest problems people have, I would agree that most cannot be solved with money.
If it did, I wouldn't find rich people who have more problems than I do. Definitely would not swap places with some of them.
Sure: If you take the same two people with the same intelligence, skills, and problems, having more money likely helps. But that's not the reality.
Given any random two people - one in the upper middle class and one very rich - perhaps on average the richer one will be a bit happier. But if you give me any random rich person, it'll be trivial for me to find a happier upper middle class person.
The difference in happiness is not huge, and the variance is high.