It not about the rate of immigration. If you immigrate a lot of high social economic status people then the amount of low social economic status citizen does no

It not about the rate of immigration. If you immigrate a lot of high social economic status people then the amount of low social economic status citizen does not increase. At the start of wars (or rather, the start of instability in a region) this actually occurs. The people who leave first is those with economical means to leave early, and those with higher education is generally those that tend to have an easier time to relocate successfully. A other way to see this in economic terms is to look at the cities which took in a lot of immigrants. The first "wave" of immigrants did not increase the social costs that society had. It was only in the later waves that local budgets started to become strained from immigration and where the average tax revenue increase from immigration became significant less than the average increased costs per additional immigrant. An economic paper around 2017 tried and sadly failed to explain this in Swedish news, as it basically got labeled as being both anti and pro immigration.