I think it definitely can facilitate the conditions for more happiness and I think it depends on the individual ad how the money was earned. If you won the lottery you may or may not be in a worse off position because it was too easy and the saying easy come easy go could make thigs worse. I would rather not experience true wealth if I was stupid enough to blow it which I wouldn't, but many do.
I think if you have earned it via a business or a sound investment then you are more likely to enjoy it far more because you know how it was created and have the tools to create more. These types of people tend to be far more confident and happier people from those who I know who are in that position. It would also depend on the individual as when is it enough and I think just being comfortable not worrying about bills and stress free is what I would consider a happy state.
I think so too. When we are part of creating something, we value it more.