(Background: Rabbi Meir of Rothenberg stated that nowadays, only a husband can force a wife to immigrate to Eretz Yisroel, but a wife cannot force a husband. The question is, if there is a mitzvah nowadays to live in Eretz Yisroel, even the wife should have the power. And if there is no mitzvah, even the husband should not have the power. In Siman 3 the Rebbe quoted the Bach, who answers that there is a mitzvah, but the difference is that nowadays it is hard to earn a living in Eretz Yisroel, so only the husband, who is responsible for earning the family income, can make the decision to move. Now the Rebbe will propose a different answer: that the mitzvah today is weaker in a certain way than it was in Temple times.)
We can say a different answer, based on the Derisha (Even Hoezer 75:3) who explains at length that Rabbeinu Meir does not hold like Rabbeinu Chaim Cohen (brought in Tosafos Kesubos 110b) who says that nowadays there is no mitzvah at all to live in Eretz Yisroel, but rather he holds that the mitzvah is not so great as it was in Temple times, and therefore the wife cannot force the husband but the husband can force the wife. And this is certainly true, for even the Maharit (Rabbi Yosef di Trani, 1538-1639) who disagreed with Rabbeinu Chaim Cohen brings a proof (that there is still a mitzvah to live in Eretz Yisroel nowadays) from Rabbeinu Meir who says that at least the husband can force the wife. Similarly, the Rosh quotes Rabbeinu Meir but does not mention Rabbeinu Chaim Cohen at all. And similarly, all the other poskim who disagree with Rabbeinu Chaim do not disagree with Rabbeinu Meir.
However, we must understand the root of this matter: what does it mean that, according to Rabbeinu Meir, in Temple times there was a great mitzvah, and now it is only a small mitzvah. Seemingly, it can only go two ways: if the mitzvah of living in Eretz Yisroel, which the Ramban counts among the 613 mitzvos, applies even today, then it is a great mitzvah just like in Temple times, and if that mitzvah does not apply, then what is the small mitzvah?
The answer to this is quite simple, but first we must remember the words of the Rif (Rabbi Yoshiahu Pinto, quoted above in Siman 1), in his commentary on Ein Yaakov, that the Sages only said "whoever lives outside of Eretz Yisroel is as if he worshipped idols" when the person leaves Eretz Yisroel of his own volition. Based on this, he explains how Rav Yehuda can say that it is forbidden to go to Eretz Yisroel - Rav Yehuda is talking about the Babylonian Jews, who were forced out of Eretz Yisroel by their enemies. But this doesn't make sense, since the Sages derived this teaching from King David, who said, "For they have expelled me this day from clinging to the land of Hashem, saying, go serve other gods." (Shmuel I 26:19) Now, David did not leave Eretz Yisroel of his own volition - he fled for fear of death! That is what he said, "For they have expelled me." So it sounds like even one who goes against his will is considered as if he worshipped idols. Also, the language used by the Gemara, "Whoever lives outside of Eretz Yisroel..." does not give the impression that it's talking only about someone leaving Eretz Yisroel, for it doesn't mention leaving, and if that were the idea, the main point would be missing from the text.
Now, the distinction between someone leaving Eretz Yisroel and someone who lived outside Eretz Yisroel all his life is not altogether wrong; such a distinction does exist. The Ritva in Yoma 38 asks how great rabbis like the Rambam could have lived in Egypt - doesn't the Torah say (Devarim 17:16) that we are forbidden to live in Egypt? He quotes the answers given by others, and then he gives his own answer: that the prohibition only applied when the Jewish people lived on their land, but nowadays, when there is a decree upon us to be scattered in all corners of the earth, all lands outside of Eretz Yisroel are equal, and the only thing that is forbidden is to leave Eretz Yisroel of one's own volition. So he makes this same distinction, but he does not mention the statement that "whoever lives outside of Eretz Yisroel is as if he worshipped idols" (because that statement applies even when one is forced out of Eretz Yisroel, as can be proven from King David). Rather, he is referring to other statements of the Sages, such as Bava Basra 91a: "One may not go out from Eretz Yisroel unless the price of two measures of flour has gone up to a sela." And there are many such statements which could be explained to mean only when one goes out of Eretz Yisroel of one's own volition. But this statement derived from King David who said, "For they have expelled me this day" cannot be any more lenient when someone is expelled (because David himself was expelled, and) because the reason given by the Ritva to be more lenient (that we are under a decree of exile) did not apply in David and Shaul's time, when the Jewish people lived in their land. So the statement applied only then, and it applied even if the person was expelled forcibly.