Let us accept his thesis that ongoing and sustained (if somewhat cyclical, and very unevenly distributed) economic growth is at least one of the reasons behind the relative peace and stability of the western world since WW2.
No, let's not. :-)
Look, if process A and process B are concurrent you have to prove A caused B. Merely saying A caused B, because it fits a particular philosophy or ideology, is a gross violation of Intellectual Honesty.
For example: is it not more likely there are feedbacks between A and B and it is more likely the increase in political stability - not slaughtering each other & not spending money in preparation to slaughter each other - was the Trigger Affect for widespread economic growth in Europe post WW2? Rather than the reverse?