Nah... this is the norm. Migration is usually in massive floods over short periods of time. Just what we're seeing now. What it also means is that we know exactly how societies cope. They cope fine. What we're seeing now is a piss in the sea compared to how people moved around surrounding WW2. And back then life was a lot harder than now. If we managed then, we'll manage just fine now.
The main difference was integration/assimilation. All European migration to the new and not so new world assimilated. Muslims will not do so. The proof is before your eyes with some suburbs of Western Europe being up to 80% moslems.
In the late 40's to mid 60's there were some mainly near city suburbs, with high numbers of migrants. All these suburbs with high number of Italians, Greeks, Slavs etc, all dissipated by the 80-90's to mainstream integrated suburbs all over metro areas and towns.