> Are they truly happier, in the sense of being more content?

The biggest thing anyone can do in their life is figure out exactly what makes them happy, and spend their money there. Don't let society tell you. People on this site likely care about computers and spend a disproportionate amount of their money on them, and that's ok. I don't care about cars or TVs, but I care about experiences and comfort so will spend money on travel and upgraded plane tickets.

I also care about agency, so tend to save money rather than spend. I want the freedom it provides more than what it can buy - typically.