The root was the destruction of the pillars of civilization by cultural marxism:

Private Property/ Free Markets
Religion
Family (as immune system against the state)
Independent Culture
Free Education 

TomK

culture

Birth rates fall worldwide

Of course because FIAT system is losing its value. Therefore, you do not want to bring human being to this world if you aren't sure that you can take care of them. Why would you give birth to someone if you do not even know that you can feed yourself not even another human?!