An important dynamic very little talked about is the fact that in the majority of industrialized countries within a very short time populations will be decreasing. The battle of the future will be who can bring in a continual stream of people to keep the economy growing. So various countries will likely be battling for highly skilled workers in the future. So the challenge with more immigration is that you have to have some robust level of job creation and growth for the existing people in the country because otherwise you will have a combination of a broken system (people come to the country and get a job, but then their kids never get jobs, or they lose their job and cant get another one), or people will resent the people who are getting jobs, or people will come to the country and then end up leaving. So lots of bad outcomes if you don't actually set things up in a good way. Countries like Germany have a really strong system of vocational jobs, apprenticeships, career ladders, etc so there is a sense that the local people have some career trajectory, so somebody else having some level of success after arriving in their country is not bothering them. Of course that's not universally true, but definitely people will be resentful in a particular area if tons of new people show up and have tons of success while they struggle to get off square one..