I think you’re reading too much into what’s not there. The poster is talking about how less people resulted in the improvement of labor conditions. In the past this has only happened noticeably through large scale death. The black death is probably the most drastic but similar has happened after both WWI and WWII. The difference is that the current labor supply reduction won’t be from death but from reduced births. However, increased power of laborers should at least be similar whether the cause is through death or reduced births. China, Japan, and South Korea are experiencing/are going to experience this first without drastically increased immigration and the rest of the western world isn’t far behind.