Trick question since I believe I already know the answer. But I'd like to hear some other views.
I believe that Economic Theory is like Psychology, it pretends to be a science, when really it is a religion.
People base their opinions on their beliefs. There usually isn't enough facts to go on, anyway.
A basic definition of what I mean:
Integrated Economy would be what the EU is aiming for. Seamless easy access for business to span borders. Favours big business.
Isolated Economy would be North America up to the 80s. Tariffs on most things to encourage local sustainability. Favours small business.
I tend to prefer relatively isolated economies because redundancy adds resilience. However, with the rapid pace of technological development I'm not sure how feasible that is, especially for smaller economies. If for example, quantum computer based AI becomes the dominant technology, we'll be lucky if there is more than one country or company with that rarefied technological capability. Such effects existed in the past, but as technology advances they become amplified.