I feel people act naively on these discussions because they are afraid of offending others, but it is common sense that a ~0.3%/year influx of immigrants with low resources over 50 years has contributed in some way to economic disparity in Sweden. Nobody is saying that immigrants are having a negative effect here, it just means that newcomers have an uphill battle versus established families that have been building wealth for decades.
Just to clarify your point, it means that the opportunity for people who were the offspring of "historic" Swedish citizens and didn't not already own or inherit substantial wealth (most people) was subtracted due to the large movements of populations.
As a result, I don't see why someone would support such a policy.
Also not to forget globalization moving populations inside countries. Which might be key effect. Globalization caused many industries to die off and basically those communities now have housing stock that is worth very little or is worthless. As the jobs stopped being there and new jobs have been created in other places which do not have the supply of new housing.
