Of course it is! Economic success is the main driver of immigration. If an economy can genuinely no longer sustain an influx, then people stop coming. Economies flex with their populations, they always have and they always will. If they didn't, then the USA, being made up almost entirely of unfathomably huge influxes of European immigrants, would have a 99% unemployment rate and would consist of 330 million people all trying to cram into a handful of Cherokee tepees. The simple act of having a larger population not only means an increase in tax receipts, but it means that there is a higher consumer base, which in turn creates greater demand, and subsequently, more jobs. We only have to look back at old Daily Mail articles from the 20's to see how this infantile anti-immigration stance has changed very little. Back then they were saying that the UK could not sustain the population increase of Jewish immigrants and later refugees. Move on a few years it was Indian, Polish, Romanian etc. The arguments were the same each time, with them spelling out doom and gloom due to overpopulation, collapsing infrastructure, not enough housing etc. Did it happen? No. Instead our population doubled and our economy jumped from 8th in the world to 5th. We are around 51st in the world in terms of population density (268 per km2) with many highly successful countries having more than twice our current level. The Netherlands for instance has a density of 407 per km2.