Pinker’s work also draws on Norbert Elias idea that culture or a change in culture is another component in how societies either become more violent or less violent.
I have never been a fan of romanticizing hunter gather societies or pre industrial societies in general. It is funny so many leftists (and some anarchists) use this idea of the mythical peaceable stateless societies that existed before state formation is just merely a rebrand of the “noble savage” myth European intellectuals developed in the eighteenth and nineteenth century. This idea was central to German and French scientific and anthropological racial theories that non-European societies were merely cultural imitators or remained frozen in time.
In any case, the question to why many societies that are essentially Western (this includes countries like Japan and South Korea) are now less violent than they were a century ago is worth investigating and Pinker’s thesis is certainly interestingly enough to give him a listen to and read.