The biggest blond stars I can name off the top of my head are Alan Ladd, Buster Crabbe and Dan Duryea.
Do dark-haired guys just film better? But then there were plenty of blonde female stars.
How many current male movie stars have blond hair? Brad Pitt’s the biggest, I guess, plus Leonardo. But among the very top, that’s about it (compared to Hanks, Cruise, Gibson, Clooney, Denzel, Russell, Carrey, Sandler, Affleck, Keanu & others)
Naturally, many more people are dark-haired than light-haired. Standards of beauty for whatever reason have encouraged the ladies to go blonde. No such pressure has existed for men, where blondeness is unusual but not necessarily desirable. Just look at hair-color sales. I’d bet that women’s products outsell mens by quite a degree, and also that most men tend to darken gray hair where a larger proportion of women are lightening dark hair.
I think there’s something to your asertion that dark-haired men film better, at least in b&w. In my experience, I prefer darker-haired actors of both sexes in b&w, it seems to frame the face better, and eyebrows are more visible and expressive. Short blonde hair would seem to be difficult to light properly, and easy to wash out, and long hair on men would be less common back then.
There, I think I’m done with my unfounded speculation for now.
Also, blond hair photographed darker in the early years: Henry B. Walthall, Wallace Reid, Arthur Johnson and others had sandy hair that looked brown on film.
Harpo Marx’s red wig photographed black in “The Cocoanuts”; he continued to lighten it to suggest red hair, and most people get the impression he was supposed to be blond. Dialogue indicated he was supposed to have red hair. (“His hair wasn’t red yesterday.” “It was a red tapeworm.” from Room Service, for instance.)
There was a brief pocket of time in the mid-sixties when blond men ruled. Michael York, Michael Caine and Robert Redford come to mind. But that was the mod era.
In color films, Erroll Flynn and Kirk Douglas were usually blond, but in the black and white films their hair seems darker. Only really light blond would stand out on B&W I think…like platinum blonde (Lana Turner, Veronica Lake), which few men naturally have.
Also, I remember learning that Elvis gave himself an extreme jet black dye job when he was starting out, thinking it would “photograph better”. It became one of his trademarks, though his real hair color was more sandy blond. The point being, that at least some people thought black hair looked better in monochrome film.