I wonder if this sort of thing is cyclical. The next dark age, caused by the earth being overrun by the fecund and illiberal peoples of the world until they can only eat themselves. Maybe a plague wipes them all out and they are too poor/illiterate/unlucky to survive it. 600 years later, someone re-invents the internet, for people to use to post that they don't want kids.
I don't think "let's make some babies to keep those extremists at bay" is the sexiest of pillow talk. But then again, I have dated individuals with severe enough views on the world where I could see that actually working. :)
My lifespan is too short to worry overmuch about any of it.