People only really change when it hurts so much they are forced to. It needs to get much worse to reach that breakpoint and critical mass. (Some reach it sooner than others ) But when it does, we need to be ready with the most logical and attractive solution to avoid them choosing fascism or other extremes. Left ideology needs better marketing, why not sell that utopian vision we hope to achieve.

Population has declined in general, especially in richer countries. This stat alone is not conclusive or a solid argument. There are better stats that proof ussr communism wasn’t bad for the people compared to capitalism.