Yeah, fast changing demographics means fast changing values, expecially if imported values. Maybe the new country will be a "better" one than what it was, but i wouldnt trust people that come in mass from failing or disfunctional societies to build some awesome society, as i wouldnt trust the government/society ability to social engineer people into model citizen in few decades. it is a process that takes often generations.

Usa got lucky bcs it integrated mostly european of "similar" cultural values of its anglo base in a pre industrial society, and later integrated the brightest from around the world in a knowledge economy. Even Latinos illegals have familiriaty with US values.