Mormons, why I didn't see One female wearing long pant from a huge meeting in Salt Lake City (out of thousands)?

Was it a religious meeting? In our culture women wear dresses or skirts to religious meetings or meetings held in religious centers. Pants are worn for casual wear or business wear.

Most women in the Church wear dresses or skirts. That is what is expected as appropriate attire for church worship services.

Look closer next time. They are there, you just didn't see them.

I know nothing of that but they used not to wear makeup or jewelry, either.