An easy and clear example as how countries need immigration to keep its economy as well as many other services alive is the policies little villages in Italy or Spain ar launching giving free housing for families with children willing to relocate to keep the school open or the local cafeteria.
As I have been spending more time in Portugal in a rural area, you see tons of abandoned houses in villages, most of them ruins. The whole region population has been reduced in the past decades as youth has left for better opportunities in the big towns, but thanks to immigration increase from europeans moving from other countries, building new homes or restoring old ones and spending money, you are starting to see how the villages are starting to get some more activity, first from the construction industry and also in restaurants and little shops.
Hopefully the changes in distribution of people will lead to a more balanced distribution of wealth. Especially now with the "WFA" possibilities, we shouldn't have to just move into over-crowded cities.