> most of these people will literally be leftovers with nothing left to contribute to the world

A lot of people from bangladesh and india are working in Russia. China and Russia are also investing, and building factories there.

> Chicken/Fish produce an order of magnitude or in some cases two orders of magnitude less pollution than cows do.

Cows are not for eating, they are holy animals in India, more like pets. I hope you are not advocating eating dogs in west!