I probably would’ve agreed with this at one point, but I don’t know now. That “Truth, Justice, and American Way” thing doesn’t play the same way now…especially with people that aren’t white. He may be the blueprint still…but as far as mass appeal…I don’t know.
the character appeals to people globally
on paper - an alien who was raised as a human (people can resonate with not fitting in/not belonging), moral compass of humanity while withholding his own powers, etc ... of course when they Americanize the character with nationalistic propaganda it doesnt hit the same
but i think his symbol/iconography alone puts the character up there (in terms of mass appeal), there are people of all races and walks of life around the world that recognizes it, people have it tatted or have it as a sticker/keychain etc, casuals still wear merch or shirts with the symbol... there are many parts of the 3rd world where you see street art and graffiti of the "S" symbol ... i don't think any other comic book character iconography has the same presence
unfortunately his stories just aren't usually as compelling or written well compared to spiderman & batman, his powerset makes it harder for him to be relatable too