I suspect the root of the problem is with the way we view our economy. Instead of measuring happiness we use e.g. GDP as a metric, but I wouldn't be surprised if a high GDP correlates with and causes unhappiness and on top of that it certainly also negatively impacts the environment.

Also, capitalism/the free market seems like a very unfair system (no need to provide examples I hope), and unfairness is also a known cause of unhappiness.

But meanwhile, instead of addressing these problems, our brightest minds are trying to make people click more ads ...