The thought experiment is interesting but the conclusion might be more radical than it appears.
Relationship based immigration would mean the existing social network of any country determines who gets in. People with no connections at all, refugees, skilled workers from underrepresented regions, have no path in whatsoever.
It might solve the exploitation problem while creating a very different one: permanently calcifying existing demographic patterns. Not arguing that's wrong. Just that the downstream effects run in unexpected directions.
RE: Love Rules