The people flooding into Europe are escaping their own repressive, backward cultures, none of which produced the philosophical discourse, political theory, architecture, science, medicine, technology, in short, the civilization that was produced by the confluence of histories that produced Europe. Those invading Europe are coming to appropriate and they are killing a golden goose that they have no capacity to replace. When they're done, as is always true in such cases, they will transform the destination into what they are escaping, so the "demise" of Europe will be thin solace.
Olaf, why do these poor former colonies lack a strong central government? Why were foreigners able to go in and make a profit, when the natives were not able to? Why are they willing to leave family and friends behind (at least temporarily) to embark into a foreign culture? Because things are better in the West. You seem to think that is basically because anything good in the former colonies was systematically sucked out and transferred to the West. I would argue things are better in the West because western civilization encouraged education and cooperation and, in the case of the USA, individual responsibility and action. I would also point out that any attempt in 2017 to correct mistakes from 1917 or 1817 are futile. It is also futile to throw money at corrupt regimes. But that is another argument.