I dont know how much of it is youth tho when its a woman to a man. Men prefer the youthful appearance because women on average (MOST OF THEM) just dont age well. Women need much more work to maintain an attractive appearance as they age and most just say "f*** it", get fat, cut their hair short, and start wearing slacks. I mean can you blame a guy for wanting someone younger at that point. On the other spectrum though there are guys with full heads of stark grey hair that women think are gorgeous. Hair, to ME, has always been equated with beauty, trust, heroism, virtue, strength and loyalty. Bald is ALWAYS the villain. These are not Hollywood created tropes, they are the way we as a species view these 2 sides of the spectrum.
Hair equals a high paying CEO, a rock star, a movie star, a business man, where bald equals an uneducated blue collar shmoe.
Even if you go towards the idea that a bald head means alpha, dominance or authority, NONE of those are going to fit with a guy who is 5-8 or less. Does a bald 5-3 guy emanate authority to you? Not usually, so we need that height to give us the stature to go with the bald head. My one saving grace is my physique but even then, I just look like a 5-8 guy who just got out of jail, not really an authority figure. If I was 6' then a shaving my head could be a "look" I was going for more than a forced way of life. Its all smoke and mirrors.