It isn't shallow. What men and women are attracted to in each other isn't identical, but damned near.
Women swooned over Carey Grant, because of his looks, but only partly because he was classically handsome. If he had had effeminate mannerisms, women would have found him less attractive. If his voice had been high pitched and whiny, women would have found him less attractive. If he'd been short, women would have found him less attractive. If he had appeared insecure, and filled with self-doubt, women would have found him less attractive.
If he had been all of those things, no-one would remember him. He would've been less memorable than Montgomery Clift. Was he handsome, though? Of course, and his headshot would've been selected above thousands of other actors, just on his looks, but if he hadn't exuded self-confidence, and had a masculine voice, and been tall and lean(but not to the point of appearing frail), he wouldn't have been Carey Grant. In fact, if he'd been Archie Leach, far fewer women would've imagined themselves as "Mrs Archie Leach."
Presentation may not be everything, but it can be the difference between obscurity and legend. And that's sticking strictly to the superficial elements, although those that transcend mere photographs.
The same is true of women. Was Marilyn Monroe really that beautiful? Her hair was bleached. Her voice and mannerisms exaggerated to an almost infantile level, and she was little on the plump side. Her figure accentuated the fertility cues that men look for in women, though, and her voice and mannerisms affected the feminity and youth that accentuate those cues. It's the same with the blond hair. One of the reasons that "gentlemen prefer blonds" is that blond hair is another subconscious youth signal.
If Marilyn Monroe had had slouched shoulders, sported her natural brown hair, had a voice like Popeye(and a matching sailor man's vocabulary), walked like a lumberjack, and dressed like a hobo, I doubt she would've captured the attention of the Kennedy brothers, much less the world.
So, where does physical attractiveness end and presentation begin? All I know is that people have tons of excuses for being less than the best versions of themselves.