There is no single reason, but inattention to what our schools, both K-12 and Universities, have been teaching in the past 20 years has a lot to do with it.
That and politicians without principle and values....except power.
[... How did this happen? ...]
If my people, which are called by My name, shall
humble themselves, and pray, and seek My face,
and turn from their wicked ways; then will I hear
from heaven, and will forgive their sin, and will
heal their land. -- 2 Chronicles 7:14