That's true, but if you look at old movies you'll see the men aren't in nearly the same good shape that men in modern movies are - if we used movies to determine what we think the population is like we'd assume there are way more 6 packs now.

It's tempting to view men from earlier eras as more manly, and may even be true, but besides fads in popular 'looks' another big difference was the near universal consumption of cigarettes earlier on.

Interesting observation, but this could simply be casting males with deep voices.

Wasn't that just caused by heavy smoking?

Casting practices has changed drastically and there's been major increase in diversity of characters in movies/tv.

There's even been a huge increase in diversity of, ex, contestants on game shows/challenge shows.

There's just simply much, much more media made now too.

You can control for that with casting. I don't think it was until Ira Glass came around that we got away from it in radio.

Looking back even further, consider the influence of the electric microphone on music. It used to be that you had to be able to project to the entire room with your own power, but now many quieter varieties of voices are able to compete too.

maybe - could just be because smoking and drinking hard liquor was more prevalent back then also

Each culture has aesthetic preferences. What you see/hear in movies and art generally is not how average person looks like, but what people in that era want people to look like. Art books sometimes even have explicit advice on what kind of people you should draw so that people like looking at them.

tl,dr: deep voices in old movies are artefact of people liking deep voices back then.