Modern Israel is a product of modern developments unrelated to ancient Israel. For starters, any idea that preventing the Jewish diaspora would have prevented the development of modern Israel ignores the fact that native Jews existed in all periods of the Levant, whether under Assyrian, Babylonian, Persian, Greek, Roman, Byzantine, Abbasid, Crusader, Ottoman and British colonial rule. The Jewish diaspora in practice is no more significant for modern Israel than the Greek expansion outside of Greece into the the Mediterranean and as far as Hindustan is for modern Greece, and this "diaspora" only provided a Romantic nationalist mythology that is no more factual than the Romantic national mythology of other nationalist movements of the same period. Jews have kept living in the land of Israel all the time, and at no point was every single Jew expelled from it unable to return until now.
Modern Israel is the product of a small class of 19th and 20th century European Jews who progressively bought land in and around biblical lands, aided initially by British colonialism and then forming a state around these lands when Britain decayed and said European Jews were able to carve a state out of their bought territories by taking advantage of this.
Basically, it's simply not true that had the Assyrians and Babylonians not conquered Israel that therefore there would be no "diaspora" and thus no need to create a modern Jewish state. In fact, Jews were able to create the Hasmonean kingdom after the successful Maccabean revolt that became something of a regional hegemony as it absorbed local Nabatean territories and survived reconquest attempts by the Selucids and Ptolemies. In fact, the Hasmoneans kind of wilfully annexed themselves to the Romans, though it's true that the Romans threatened the Hasmoneans with war.
After that, we can also trace some independent states in the general area of Israel, even if not ruled by Jews. The Kingdom of Jerusalem, a number of Arab polities. Any of this could have developed into a nation-state called "Israel", though granted, one where Judaism is not the only identity marker but a combination of all cultures that have lived in and around Israel.