The Chassidishe Gatesheader…
You say “Kahane was a fool”?!? You obviously never spoke to him in person or you would never make such a horrible remark. Rav Kahane ztzvk”l was ahead of his time! And name calling a Jew who died al kidush Hash-m (whether you agreed with his hashkafos or not)?!?!? You should go to his kever to ask mechila.
To answer the original question posed…
The Chazon Ish in his Mitzvos haTeluyos ba’Aretz states that one may leave Eretz Yisrael for a business trip, to get a shidduch, and for a few other short term reasons, BUT it has to be only TEMPORARY. He concludes with ??? ?????? ?? ???? – to SETTLE (i.e. permanently) in chutz la’Aretz is FORBIDDEN.