What kind of Jews dress in the same way as their ancestors 100 years ago?

Clothing styles have changed completely more than once. Today's suit did not exist seven or eight centuries ago. In the time of the Sages 15 centuries ago, most Jews wore white flowing garments. Sandals were worn in the non-rainy months. Pants were worn under one's robes if at all. Inexpensive garments were often made of hemp.

The one thing that is unchanged is that religious Jews have always kept their bodies fully clothed; thighs and torso especially, both men and women.