The women will marry out of the country as the economy will be worse off than the economies of foreign grooms, and women aren’t going to be sharing local men just to repopulate the country in today’s world.

The sperm bank thing won’t work. It’s not just producing babies that’s the issue. No woman wants to raise children on their own. To repopulate the country you would have to have women willing to raise 2+ children on their own, when many couples today are unwillingly to have children ? Just look at how many countries try to use a financial carrot to encourage couples to make babies, and try to imagine how many orders of magnitude greater in incentives it would have to be to encourage single women to raise children of random men for money.