Higher salary justifies higher rent.
But higher than London or HK??? Really???
I’d guess other cities are much larger, and include what would normally be suburbs here. SF rent isn’t higher than Manhattan, but New York statistics include Queens. I’d guess London also includes some streetcar suburb type areas, don’t know about HK
SF has better pay in general compared to London and Hong Kong. There are also more condos in those cities than SF so more supply.