If you want to scaremonger about low fertility, pick a better example. Japan doesn't seem like such a bad society to live in to most people.
Of course it has its social problems, like any other country, but Japan's oppressive work and gender norms have little to do with its aging population. If anything, the Japanese example shows that a rich country can maintain a high quality of life even in the midst of very low birth rates.
They're not putting old people out in the streets, either. This is a country that treats its elderly significantly better than we do here in the US.
By the way, the places in the US that look most like Japan are gentrifying neighborhoods in coastal cities, not the towns and small cities of the heartland in which anti-immigrant sentiment seems most fervent. The latter generally have relatively high birth rates among women of childbearing age.
Are you under the impression that immigration to the US is a problem? You seem to have moved to a more skeptical (at least) stance regarding immigration that would generally be seen as further to the Right. I apologize if I am mistaken.