It is not at all clear that Professor Lustick, the author of this article, sees a “likely” set of consequences for Israel. He does not appear to be predicting what will happen. Instead, he is saying what will not happen and what might happen instead.
From this article, it is clear that Lustick believes that there will never be a two-state solution. He believes that too much has happened since 1980 to make that a possibility. That means that he thinks that there will only end up being one state between the Jordan River and the sea. Clearly, he believes that Israel will, at least initially, be that state.
From there, Lustick’s vision is less clear. He believes that the one-state Israel would be fundamentally unjust. He compares it to places like apartheid South Africa. He says that enormous pressures would build up within the society as the Arab population grew and as Israel oppressed that population. What happens after that is anyone’s guess. One possibility is that some coalition of secular Arabs and Israelis would take control. Another is that ultra-Orthodox Jews and Muslim traditionalists would join together to take power.
Thus, Lustick is not predicting a specific future. Rather, he is saying that a two-state solution cannot work and that a decent one-state solution might possibly be feasible.