the available evidence suggests that winning a big lottery prize doesn't typically make people all that much happier.

Maybe typically people use their winnings in a wrong way. For example, they buy an expensive car, go to an expensive vacation, etc. And a year later, there is nothing left. And they know they will probably never win the lottery again.

It would be interesting to have a data on a subset which instead of doing this does something smart, such as retire early. Or some other big change in their life, for example pay for education they didn't have, so even when the money is gone, their everyday life remains different.