superman's the anthropomorphisation of america's innocence.
the superman of the popular imagination isn't the rage-of-the-immigrant superman of the 30's. he's not the grim one who dealt with wife beaters and corrupt politicians.
it's the superman of the 50's. having pies with ma and pa kent. a nuclear family superman with supergirl and his pet dog crypto. there's an underlying calm. it's a superman of prosperity and peace. a superpower (geopolitically, not in terms of lazer eyes and flying).
it's what's so poignant about him now. he's something that's lost. an innocence and a calm. a domestic bliss.
superman after watergate, vietnam, rodney king, 9/11, iraq, blm, trump, etc. can only be a bitter reminder of an ostensibly gentler, simpler time.
all of which of course speaks to something we go through in our own lives. he was a child. the world presented to us by superman in the 50's was of childish wonderment. we've lost that and thus superman will always speak that arrested development which wishes we'd never grown up.
the only really succesful superman stories of the last few decades have reflected this; they're either intentionally harking back to that era or they're literally killing superman.