The ‘demographic crisis’ is one of economics and states, not the persistence of the human race. The ratio of the old to the young is increasing drastically. Our global economic systems are simply not designed to support this. Our states cannot exist —as they are—without constant growth and those that fall behind are left behind.
The solution to the ‘demographic crisis’ is to move towards economies that are not based on constant growth so that the phenomenon is no longer a problem. Ironically people will probably be more interested in having babies in this scenario as well. Global capitalism is depressing, soulless, and does not make me go “wow I hope my decedents get to experience this.”