Jose Fly
Fisker of men
FYI, even though this survey is from 8 years ago, I think it still provides insights into the reasons behind the decline shown in the OP.
https://www.barna.com/research/six-reasons-young-christians-leave-church/
Reason #1 – Churches seem overprotective.
Reason #2 – Teens’ and twentysomethings’ experience of Christianity is shallow.
Reason #3 – Churches come across as antagonistic to science.
Reason #4 – Young Christians’ church experiences related to sexuality are often simplistic, judgmental.
Reason #5 – They wrestle with the exclusive nature of Christianity.
Reason #6 – The church feels unfriendly to those who doubt.
https://www.barna.com/research/six-reasons-young-christians-leave-church/
Reason #1 – Churches seem overprotective.
Reason #2 – Teens’ and twentysomethings’ experience of Christianity is shallow.
Reason #3 – Churches come across as antagonistic to science.
Reason #4 – Young Christians’ church experiences related to sexuality are often simplistic, judgmental.
Reason #5 – They wrestle with the exclusive nature of Christianity.
Reason #6 – The church feels unfriendly to those who doubt.