For about the last 25 years, I've traveled to Europe yearly for work conferences (mainly UK, but also Germany / France / Spain as well).

I have no specific knowledge or special insight, just observational comments.

Over the same period, the EU’s GDP per capita fell from 76.5% of the US level to 50%. Even the poorest US state – Mississippi

I wonder how much these data points are the result of migration....meaning if you import millions of very very poor immigrants its going to affect per capita numbers dramatically.

When you are in Europe, daily life in the "non migrant" areas of town looks fairly normal and doesn't seem to reflect "mississippi poverty levels" at all. There are lots of high end restaurants, hotels, cars abounding. Most middle-class and above professionals seem more or less on-par with their US counterparts....sure their housing is smaller, their cars are smaller, but daily life seems much closer than these stats indicate.

However, what I have witnessed, is the "migrant areas" have spread significantly over the last 25 years. From what was very small orderly "migrant neighborhoods" to pretty much "half city-sized slums". It really does seem like too-much too-soon....I don't see how these areas are ever going to integrate.