but their many relationships are entirely performative. and they have built up their entire life as one big act.

Is precisely the part i disagree with if you're going to generalize the way you did in your first reply. Hence talking about the experience even with honest meaningful deep non-performative relationships.

it means they are mentally ill.

Psychological health indeed impacts it, hence why i brought up depression and anxiety to name just two of many conditions that could contribute.

The wealth disease, on the other hand, is probably generalizable in the way you're suggesting. I couldn't really care it someone is sad about being ultra-wealthy. Maybe they should give it up and be a depressed laborer like the rest of us.