This. An incredibly rich top 0.1% percent could skew GDP per capita a lot, but a happiness index not so much.
Simplifying things to the extreme, take 100 people where half of them earn $1 and are unhappy and half $2 and are happy. Give one person a $150 raise-- you just doubled the GDP but at best increased happiness by 1%.
It is no secret that a small percent of people have been getting very rich [1].
