>>513427124 (OP)There are two simple answers here.
The first is that George Costanza is the greatest-ever televised depiction of male insecurity and pettiness. We have all had moments of insecurity or pettiness, so even when George is flying off the handle on something crazy we can usually still relate on some level. He's also ugly, short, bald, kind of smart but without any marketable skills. Much more relatable to the average /pol/tard than a sitcom with a stable family where the parents work good jobs.
The second reason is that it depicts a comfy 90s we all want to retreat to, quite badly. No internet, no overstimulation, yes the dating market was fucked but people still had hope and tried to meet each other. Even Costanza, occasionally, could get laid, get a job, and so on. The show's comedy often revolved around the arbitrary nature of social norms, status, trends. Still very relatable today.