The study that looked at subjective well-being in 16th century Spain concluded that subjective well-being mirrors subjective economic inequality. Without going too deep, it seems that relationship continues to hold in the modern time period of which you speak. Subjective economic inequality has increased, and subjective well-being has declined.
But that does question just how important subjective well-being is if all it is is your perception of how much better off someone else is.
But that does question just how important subjective well-being is if all it is is your perception of how much better off someone else is.