I agree that people underestimate the impact of the first two industrial revolutions while overestimating the impact of the third, if that was your point.
I'm not yet prepared to agree that the scale of bellicosity in the 20th century was the result of labor displacement (as opposed to, say, the results of the mechanization of violence). I mean, like, https://en.wikipedia.org/wiki/List_of_conflicts_in_Europe.