Why is it difficult for developed countries to go?

1. The immigration policies in developed countries are usually strict, and it takes a complicated application procedure and a long waiting time to obtain citizenship or permanent residency.

2. Developed countries often have higher requirements on the quantity and quality of immigrants, so the success rate of applying for immigrants is relatively low.

3. The cost of living in developed countries is generally higher, such as housing prices, food, transportation and medical care. Therefore, for some people with poor economic conditions, living in developed countries may bring greater economic pressure.