No. Cultures matter. Homogenous society > GDP

The history of the US would imply otherwise. In any case, Germany definitely needs immigration for economic reasons as the population is aging.

If you are implying the downfall of the United States during the 20th century. You've made my point for me.

I say it all the time.

which country?

When you import the third world, lower standards to accommodate the worst of society...who's actually surprised by this?