Despite a several decades long decline in total fertility rate, most demographic models I have seen assume that lifetime fertility will magically bounce back to

Despite a several decades long decline in total fertility rate, most demographic models I have seen assume that lifetime fertility will magically bounce back to replacement level. Underpants gnomes models. Bounce-back could happen, but there is no understanding in governments of why the decline is occurring, nor what it takes to reverse it,* so it is unlikely. * Exhorting people to return to traditional family values, as the new PM of Italy does, is likely to crash fertility faster.