I believe that, over the long term, it is inevitable for a single state to emerge.
The reasons for saying that are many, but I'll just mention a few.
Demographics are not on Israel's side. The principle of Demographic Transition - a universal phenomenon - means Israel, like other advanced countries cannot even replace its population. Palestinians have rates of natural increase on the order of places like West Africa.
This does not just mean a great population disparity in future.
It shapes the age structure of the populations, Israel will become an old society while, as in other Arab lands, Palestinians have a young population, roughly 60% youth.
Until now, Israel has been able to get immigrants to temporarily alter this changing population structure, but this will not continue to be so. There are no more large Jewish population pools like that of Russia under the Communists, at least not in places where people are willing to trade a comfortable life for life in Israel. And the longer the conflicts continue, the less attractive is Israel as a destination for any immigrants.
Israel also spends a shamefully large amount of its GDP on military matters. It gets a big subsidy from the U.S. - and will that continue indefinitely? However, it far, far outspends that. Just consider what happened to the Soviet Union, a nation whose economy had many structural similarities to Israel’s.
Also the generation with lifetime memories of the Holocaust is about gone. These people had fears beyond measuring which contributed to Israel’s often unfair stance towards the Palestinians.
Again, the world has dramatically changed from the world of 19th century nationalism, the environment which fostered Zionism. Implicit in that world was that countries are defined by ethnic identity. The world, at least the advanced world, simply no longer believes that. Indeed, the notion is starting to look as outmoded as ideas from the Middle Ages.
Israel has maintained, in the words of an early Zionist, an “iron wall” towards its neighbors for sixty years. The psychology of most people just will not allow that to continue forever. People want to just live and love and trade and enjoy life.
The Arab states originally were against Israel’s establishment, and they had every legitimate reason to feel so. But Arab states all accept the reality of Israel today.
Even parties like Hamas, so demonized in the Western press, are willing to talk and reach a modus Vivendi. They withhold recognition as a legitimate bargaining position. The U.S. went many years without recognizing the Soviet Union. Then it recognized it and constructive exchanges became frequent.
