I know this is a really difficult topic to discuss, and i'm trying to be careful while talking about it, but i'm kinda looking for somebody to talk to about this, so here goes some more thoughts:

Contrary to the 19th and 20th century where a labor shortage was a constant theme, in the next 200 years (assuming the population really does go down symmetrically) there'll be a labor excess, i.e. functional underemployment (i.e. wages being too low to sustain a proper living). Social spending like UBI (universal basic income) are really just a patchwork and leave the population at the whims of the government, which is why people don't like it so much, but still recognize its necessity. Long-term, matching labor supply and labor demand is the only meaningful way, i.e. drastically reducing labor supply.