We should be clear about this because even at scale immigration can work well, and be a net benefit economically.
Another problem Sweden though is that they also didn't import people with compatible cultural values. So you have a population of people who are unable to economically contribute, and often unwilling to integrate.
I just wish people listened years ago when people like myself suggested it was likely to play out like this instead of being so mean and accusing us of all having hateful motives. There's no going back now.