The black death was a great time for worker's rights. Terrible for other reasons but great for worker's rights.

Population decline may cause some issues around aged care, and I'm worried about how the demographic impacts might impact progressive politics, but overall I think having kids causes more harm to the working class than not. Which is probably why Japan has more faith in capitalism than basically any other country surveyed, everything is downstream of the unemployment rate and Japan's is remarkably low.

EDIT: All this is probably why Elon Musk wants you to have more kids.