GDP (in some form such as per capita, real per capita, real per capita change, etc.) is the widely used proxy for an area's well-offness. But standard textbook discussions note all the reasons that it is a poor proxy. There are even experiments with the alternatives such as Bhutan's Gross National Happiness.
Economists have been doing "happiness" research for some years and report (gasp) that (i) more material wealth does not easily map to more happiness; (ii) happiness is elusive; (iii) happiness is hard to measure. A good friend remarked, "don't economists take freshman philosophy"?
Joseph Epstein's Envy is a delightful antidote. In fact, it is better than the philosophy 101 I recall. Open to almost any page and enjoy. "... consider envy as less a sin than as very poor mental hygiene. It
blocks out clarity, both about oneself and the people one envies, and it
ends by giving one a poor opinion of oneself." (Location 781 on my
Epstein thinks that envy is the worst of the seven deadly sins. He does not nominate those who stoke envy for political gain as engaging in a worse (and eighth) sin. But he comes close. "... the doctrine of Marxism is many things, but one among them is a plan of revenge for the envious. How else can one view Karl Marx's central idea, the perpetual class struggle ..." Location 470. Stoking envy, then, is the same as stoking fantasies of revenge.
Here is up-to-date revenge: "You didn't build that." So you don't really own it. We all do. So fork over.