Ghettos to me are just the natural destination. People these days try to conflate immigrants all as wealthy immigrants to downplay immigrant successes in upward mobility but pretty sure most non-white people across Europe and the US came over as refugees/asylum seekers usually from wars from invading Americans and Europeans. My impression of what immigrants across Europe are mad about and it's all former colonial holdings that were Muslim countries and have been proxy war central since after the Ottoman empire fell.

They're broke. They're traumatized from a warzone and/or poverty (level of poverty unfamiliar to Americans and Europeans) and then traumatized again from the uprooting their life from tgeir community to another country where they will undoubtedly face some level of racism and language barrier

They're broke so of course they'll end up in poor communities and communities of similar background where they can function day to day with less language barrier issues. Language barrier assimilation. Classic and ongoing solution for people is their children learn the language in elementary/middle school and as elementary/middle school children, they're helping their parents fill out paperwork and talk to doctors/school admins/whoever. Why are children of immigrants so resilient and resourceful but oftenly not so whimsical as kids with long lineages in a country, those children often are doing adult stuff from a very early age to support old people in the community that have trouble learning the countries language. Early age responsibilities mentally age kids quick

Then as the children grow up make money and the neighborhood economically stabilizes from a large community of hard working immigrants, now the white people want to move in for all the high quality food and grocery stores. Not the best landscaping and fresh paint buildings, but possibly the most convienent neighborhoods to live in now that the neighborhoods economically grown and stabilized.

So convienent and ethnic while still mostly anyone under the age of like 50 can speak the countries primary language. There's very little active efforts to force assimilation. It's just children that grow up watching the same media as all the other children wanting to fit in growing up. I don't know what assimilation program even means when Europeans keep talking about it's necessity and using the US as a measuring stick of assimilation program success. The US barely does anything in that regard. Just let's it play out over a couple generations