It may be true that at this moment the world is less violent than it was in the past but that is a statement about our current status and we cannot extrapolate from that to say that the world is getting less violent since things can change quite rapidly.The world is getting less violent …
The more precise question is: why has war declined? I do agree with his analysis but I am less sanguine regarding the future.Why is war declining?
His argument is not new and has, despite the claims in the OP about the “media”, been something that has been discussed in the media at least since Thomas Friedman’s “The World is Flat”. Fear sells, and so, I do agree with the OP to the extent that we are led to believe that things are getting worse.
My reason for not being too optimistic is that economic self-interest in the form of trade relations is not the only or even primary motivation governing international relations. In addition, economic interests are not monolithic. The interests of the military-industrial complex argue against peace and stability.
The nineteenth century was the age of progress and there was a great deal of talk about world peace. Things obviously did not turn out that way. I see no reason to think that things are fundamentally different today.