The problems listed in the article are real. we’ve built a system:
Where a lot of economic growth stems from an increasing supply of (cheap) labour
That relies on people of working age being able to financially support a retiree class.
Both of these are going to fall apart if the population stops growing. The smaller group of working age people won’t be enough to support the amount of retirees, and without population growth there’s no economic growth.
It’s sad that economists correctly see all this coming but then conclude that the only solution is “make more babies.” It’s short term thinking almost by definition, because in the limit it’s rather obvious that at some point we will not have the resources to support any more people. And the closer we get to that limit the less each individual person will have (even worse when wealth is not equally distributed).
Unfortunately I don’t see any economist putting forth a plan that accepts population decline and alters the system to account for it. It wouldn’t be easy but it seems no one is even trying.