W. Germany started accepting Turkish 'guest workers' decades ago, initially with the understanding that families would stay in Turkey and the workers would never be citizens. I think that has been declared illegal by the EU Human Rights or its predecessor. Now, with this wave, it will only get worse, especially with NO WORKERS!
If a country taxes the working people to the point where they do not feel like they can afford to have and raise children, and uses the tax money to support the takers who live off taxes, you will get less and less children from the workers and more children from the takers. When the workers quit reproducing new little workers, then you have to import new workers -— who will then also quit reproducing when they are taxed too much as well and can’t afford to have children of their own. So, if it takes $X to raise a child, government will have to decide if they want to leave the money with the workers to raise another worker child, or take it away and give it to the takers to raise another taker. So far, it appears the takers are winning.