[DaedPsyker]

While I understand the concept it hasn't always borne fruit for example in the case of ww1. Sure Eastern Europe was less coupled but that wasn't true of western Europe.

I think too much emphasis gets placed on the material, it is the basic needs of humans after all. However many peoples material needs are satisfied to a absolute basic level already, after that there is diminishing returns.

Take my home of Northern Ireland. In the current state most people have absolute coverage of material needs. Yet there is a fairly large cohort of young that join military groups. In fact one of fundamental problems is a lack of purpose, an immaterial concept with no inherent value.

Europe became peaceful during a stage of existential threat of Soviet invasion. In that Western Europe had a purpose.

[DaedPsyker]

I should also say that economic coupling works best with similar countries, similar economies, views etc. I.e. France and Germany.

Economics will not however solve issues that go beyond money. Both China and US are ideological, those views won't coalesce through money.

[inglor_cz]

This concept failed multiple times.

Yugoslavia had a common market and a lot of mixed marriages.

Austria-Hungary had a common market whose collapse after 1918 did damage to all the successor countries.

The USSR, while being a not-capitalist society, was very much economically integrated.

So was Iraq and Lebanon prior to their civil wars.