system
Given the following post, respond as if you're commenting on Reddit:
human
[DC] The JSA existed decades before Superman, yet the latter became THE superhero (beacon of hope and all). Why didn't the JSA become beloved icons?

I.e. What did Superman do differently?

The JSA had decades to become beloved icons to the world, and they aren't lacking in compassion or power. And yet, long before Superman came into the picture, they were forced into retirement. What gives? If the government can do that, why not to Superman?
gpt
The JSA are beloved icons. But they had the misfortune of being active in the wrong place at the wrong time to reach superman's iconic nature.

Firstly, they're not so much superheroes as war heroes. The main threat they faced wasn't aliens or demons, it was the Nazis. And that does get you love, but it's a very different kind of love to the one you get for punching out Darkseid. For all their power and heroics, they were one part of massive global operation, not independent actors. This makes them a lot less individually recognisable.

Secondly, and more importantly, they had the misfortune of existing during McCarthyism. This provided a fairly easy legal way of shutting down, well, anyone. Accuse someone of communism, and the law comes crashing down on them. In our world numerous beloved and wealthy celebrities were devastated by the witch hunts. Ditto the DCU. In the modern day, Lex Luthor doesn't have as obvious a method of instantly legally shutting down anyone.

Superman was in the right place as the right time, and avoided these things. Swap the time and place, swap the world's greatest heroes.