The article cited does a good job of looking at various explanations.
The "self-fulling prophecy" objection is perhaps the least likely of all explanations.
(edited for brevity & emphasis)
OBJECTION #1: “What if the Regathering of Israel is just a self-fulfilled prophecy?”
Let’s look at a couple of responses to this objection:
First, ... The Romans, for instance, to whom the last and most extensive scattering of the Jews is due, conquered many nations; generally they allowed these nations to remain in their own land if they would submit to Rome.” Moreover, the Jews would hardly wish to instigate the fulfillment of this portion of the prophecy! Josephus estimated the fatalities at 1.1 million Jews during this time.
Second, as the Bible predicts, it is unlikely that the Jews could retain an identity without a government and a centralized place of worship. Hosea predicted, “For the sons of Israel will remain for many days without king or prince, without sacrifice or sacred pillar and without ephod or household idols” (Hos. 3:4). Hosea predicted that the Jews would be scattered for “many days” without a “king or prince.” They would hardly wish to self-fulfill this prediction!
Moreover, it would be incredibly difficult to keep a national identity without a king or prince to govern the nation. Likewise Ezekiel predicted that the kingly line would be suspended until the King Messiah came (Ezek. 21:25-27 “Remove the turban and take off the crown… this also will be no more until he comes whose right it is”). There has been no king in Israel since this time (587 B.C.). The Maccabees were not from the line of David or tribe of Judah—neither were the Herods.
Third, the Jews have not regathered ONCE—but TWICE. If the regathering of Israel was a lucky regathering of religious zealots, then it would need to explain not just one fluke, but two. Therefore, the improbability of one self-fulfilled regathering is multiplied exponentially by a second. The first regathering was under Ezra and Nehemiah.
Fourth, other nations have tried to regather, but they have repeatedly failed. Robert Newman writes:
“What are the probabilities that a people group will be globally dispersed, yet retain its identity for centuries independently of a homeland, survive almost continual persecution and harassment, and then return to reestablish their nation? Few of the peoples from Old Testament times survive today as distinct ethnic groups: The people of Moab, Edom, Nabatea, Philistia, and Assyria have all disappeared, having blended with successive migrations of Arabs and others into the area. Coptic (pre-Islamic) Egyptians and Samaritans survive, but they stayed within or close to their homelands. Given the upheavals in the Near East, only about a tenth of these people groups have maintained their ancient ethnic identity in the region over the centuries.
The Jews, who were dispersed globally, faced much lower odds of retaining their identity outside their homeland for over two thousand years. That a globally-dispersed group would return to their native land and resettle it after two thousand years is unique in history. ... Perhaps the closest analogy would be if the Amish or Mennonite communities returned to their homelands and formed a new nation, although these groups have only a 500-year history.”
If this was so easy, then why haven’t other groups been able to do this?
Fifth, the Jews regathered despite horrendous opposition.... For half of their history, over eighteen hundred years, they have been scattered from their homeland into nearly every nation on earth.” It would be a hate filled insult to say that these Jews did this intentionally (to self fulfill this prophecy), considering the Russian and German persecution of the Jews.
Kellogg writes, “Nearly every influence which might obliterate a people has come upon the Jews over the centuries, as upon no other nation in history, and yet they still survive today…
There are roughly six million Jews in Israel today. This was roughly the amount of Jews killed under Hitler’s Third Reich. If this prophecy was self-fulfilled, it was done so under tremendous opposition. Hitler was hunting down these people in their houses across Europe and systematically sending them to death camps to be burned alive!
Thus, this wasn’t an easygoing regathering of scattered people; it was an arduous and tortured regathering of persecuted people.
Deuteronomy predicted that the people would “become a horror, a proverb, and a taunt among all the people where the LORD drives you” (Deut. 28:37).
Sixth, when the Jews tried to regather, they repeatedly failed. The Jews tried to assert themselves over the Roman Empire twice before, and they failed miserably.
Josephus estimated that 1.1 million Jews were killed in A.D. 70. There were additional casualties in the Bar Kokhba Revolt in A.D. 132. It wasn’t until secular nations gave them this authority that they claimed it.
This is why anti-Semitic conspiracy theorists believe that the Holocaust was a hoax. They believe this, because the Jews got their land back as a result of this atrocity. The United Nations voted Israel into existence as a nation. Even the Soviet Union voted for it! Until this happened, Israel could not buy or import weapons. In fact, Great Britain had a naval blockade on Israel, confiscating guns that Jewish settlers smuggled in. Atheistic governments (like the USSR) would hardly wish to fulfill Bible prophecy.
Seventh, the institution of the nation of Israel was largely a secular movement—not a religious one.
Religious dogmatism and zealotry can explain fervent and unrelenting motivation. But it doesn’t explain the regathering of Israel, because Israel is largely a secular state—not a religious one.
In order for this explanation to work, we would need a sufficient religiously motivated (i.e. Bible-believing) agenda. But Israel’s regathering was largely driven by political and secular motives (e.g. Zionism, Theodor Herzl).
Even this secular state of Israel was predicted in the Bible, which states that the regathering of political Israel will precede its spiritual revival (see Ezek. 11:17-20; 36:26-28).