No they have not forgotten, I am one of them so will give you some insight.
They assimilated, got jobs, paid taxes, blended in and adapted to the culture.
Now even they don't agree how some of the new refugees isolate themselves, demand cultural changes and use the system. Some believe that they are simply using and not respecting the country these old immigrants help to build and love.
Very true Grunta, I and my family were migrants as well.
It was a different time 60 or so years ago, Greeks, Italians etc were still from the western world with the cultural difference mainly being the type of food they ate.
Today it's completely different, The so-called refugees we see today are polar opposites to the way we live and think, culturally, religiously, ideologically, politically, most of them come from countries where their lives are run by their religion and they bring it with them along with all the trouble that comes with it.
So what happens when you bring together such differences, more harm than good unfortunately, I'm talking generally here as there are always exceptions to the rule.
As a microcosm of society take a look at prisons for instance, if you as a white guy were in there where would you hang out and who would you associate with? like everybody else, you'd be drawn to your own kind, you won't see too many white blokes make a bee line for the all black group in the prison courtyard (unless you like to live dangerously) or a protestant hang with Hindu group or even worse, a Muslim heading for the group of Jews.
This isn't racist before somebody objects, it's a fact of life, it's what we are.
For it to work, Immigrants and legitimate refugees, if they really want a better life for themselves, need to adjust and accept OUR way of life and OUR laws and learn OUR language and leave all their religious and political baggage back in the country they came from, which you would presume it was the very reason they left in the first place.