I blame the Ottoman Empire. Not because it’s their fault, just because, since they’re not around any more, I won’t offend anyone by blaming them.
Seriously though, I think we have entered into the area of flimsy nation-states. Not flimsy states mind you; Syria, Egypt, and Jordan, at least, have well-defined borders and functioning administrations. It’s just that the connection between a cultural nation and a political entity is pretty tenuous in this region.
I think that Palestine (not the historical concept of Palestine, I’m taking about the geographic entity) was just Britain’s name for a chunk of the Ottoman Empire which they administered as a district. There have been serious movements to unite all the Arabs into a single country, e.g. the United Arab Republic, which existed only for a few years and consisted only of Egypt for most of the time.
The movement was doomed, since the Arab world was divided in many ways. The chief fault line was North-South, with socialist, Soviet-leaning Egypt, Syria, and Iraq lined up against Western-leaning Saudi Arabia and the emirates. Syria and Iraq even shared a political party, the Ba’ath, with each country’s chapter claiming to be the TRUE Ba’ath (“We’re for unity and you guys aren’t! Nyaa nyaa!”)
As to current Palestinian possessions, I don’t know why the Israelis and Egyptians didn’t get the Gaza Strip transferred back to Eqypt. It seems like Cairo would provide a state apparatus which has been so lacking in the formerly occupied territories.
Jordan turned down a chance to administer the West Bank in the early 90s, if I remember correctly. I think Golda (I can’t spell her last name) was claiming that Palestinians living outside Israel proper were really just Jordanians. I don’t know if I agree since I don’t know what a Palestinian is either.
So my short answer to the topic question is I don’t know. I just took a long time to say it.