isn’t this “affluenza” something rooted in guilt and which leads to near-conscious self-destructive actions?
Not exactly. "Affluenza," is loosely defined, and definitions vary, but was popularized as a defense presented at Ethan Couch's trial with the premise that his killings were due to psychological effects of being wealthy and the lack of boundaries it afforded. Nowadays it's generally used to mean a behavioral illness caused by wealth/affluence.