Even if the monthly salary of the takeaway is not bad, the minimum monthly salary of the cleaning staff in Beijing is 2,700 to 2,800, and the high salary is more than 3,000, which means that tens of thousands of cleaning staff in Beijing are basically foreigners.
Watch the news. Some foreigners have natural disasters every year in their hometown, or they are too poor to have good jobs in the local area.
Some foreigners would rather suffer than stay in Beijing, and feel humiliated when they go back. Secondly, Beijing's business and medical culture is much better than many people's hometown, and some foreigners like to stay in this atmosphere.