You're comparing what exactly? The photos in the article with the girls you see on Instagram? The photos in the article have way too much contrast and everyone's expression seems a bit surprised.

I don't think enough generations have elapsed for any genetic differences. If anything, diet and lifestyle, but I think most likely it's fashion and makeup and comfort infront of a camera and cultural understandings of beauty.

I understand your general point, but I don't think the specific pictures in the articles are good examples: the ladies look about average to me, especially if you remember that the people in the pictures were poor and not selected for beauty (if anything, someone beautiful enough would probably work a different job).

Many more people can now access dental/orthodontic treatments and minor cosmetic procedures. Getting your teeth straight makes a big difference to your appearance and make you more likely to smile in photographs.

From what I can see on that old photograph they look completely normal, about the same level of attractiveness as what I expect to see in an average high school or college.

Phossy jaw, unfortunately.

And of course they're stuck working 10 hour days for meager pay (even less for child workers) for cruel and (literally) poisonous match companies.

Go to the slums of Dhaka or Lagos today and report back how many beautiful people you see.

Your life actually has huge influence on your face (which is a "mirror of the soul"). They lived a miserable life and that's what you happen to see here.

Nutrition is a big factor.