Japan, Korea, Germany are also in line and also India (with successful space program without immigrants). There are many countries which are successful without immigrants, some of them are even democracies.
>Japan, Korea, Germany are also in line and also India (with successful space program without immigrants).
This is just plain wrong, in the case of Germany. Germany has a huge immigrant population, and has since WWII when they brought in tons of Turks to be laborers there. There's an enormous Turkish population in Germany, and it's not new. Germany probably would not be where it is now without them.
Japan and Korea don't have many immigrants, it's true, but they were both occupied by the US for some time (and Japan still is, in a way, as is Germany).
I hope your not including India in your list as an example of ethnic uniformity, are you even aware of the vast number of different cultures and languages spoken in India? India stands as the original melting pot since ancient times. Oh and it also has the one of the largest immigrant population in the modern world.