Not only has integration failed in Europe, Australia, and Scandinavia, integration and so called 'multiculturalism' has failed everywhere it has been tried. This is why so many nations in Asia and Africa want nothing to do with it at all. They have no tolerance for Liberal pie-in-the-sky nonsense.
"Multiculturalism" is exclusively a concept of Western nations.
"Multiculturalism" replaced the "melting pot" where we limited the number of immigrants and they either adapted to American values and traditions and language or did poorly. Yes, in the big cities, they still had their neighborhoods (ghettoes), but out in flyover country, they learned English, adapted, and did well if they assimilated.
Fragmentation is the current goal, however, not assimilation, and the result are distinct groups which can be pitted against each other.
In other news, West Side Story (an ethnic street gang knockoff of Romeo and Juliet) is still being shown on the movie channels. Wonder why?