“If it was so easy then we wouldn’t need these YWN posts about tznius. ”
It’s not difficult physically. You can find modest clothing. It’s not hard to get dressed. What’s harder is to fight the yetzer hara. And women have a yetzer hara for being immodest and for following the prevailing culture. When you see an immodest woman, you are seeing a person who is run by her yetzer hara.