Yes, it can buy happiness, but either temporarily or of a different kind than earnt happiness. On one hand, you'll be rich, and thus can buy anything you want, but you might not have a partner that loves you because of your... well, you-ness, just the money. So that's one kind of happiness, and the other you may have a loving, perfect relationship with the girl of your dreams, but live in a flat in a rough part of London. Two sides of one coin, in my opinion.