In order to do that the immigrants would have to pay enough in taxes to make up for the loss in utility by the preexisting residents. Some groups of immigrants, such as immigrants resembling the current Mexican illegals, may not be able to pay that. Furthermore, the same political groups who want more immigrants would oppose such a plan to the point where it won't be feasible.
And the fact that they have children in this country is part of what decreases utility for the people already in the country.
New chapter!
This is a new thread to discuss Eliezer Yudkowsky’s Harry Potter and the Methods of Rationality and anything related to it. This thread is intended for discussing chapter 102.
There is a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author’s Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: