They might not be able to remain there permanently. A 50% immigrant Germany is a Germany with no gibs. The immigrants will have little interest in Germany once the welfare state collapses. Mass repatriations have happened many times, historically. Not saying you’re wrong. I don’t really know what’s going to happen, same aa everyone else. With the U.S.A. too weak to bomb their ancestral homelands at Israel’s bidding, the situation might become stable enough for returning home to be appealing, especially if combined with no subsidized lifestyle off Germans’ tax money.