I don't think that many Israeli Jews no longer believe in a key part of the Zionist narrative. It is just that the Zionist narrative has evolved to better reflect historical research.
A total of 47 percent of Israeli Jews believe that Palestinians were expelled from Israel during the 1948 war, with 39 percent saying that "The refugees left due to fear, calls of leaders and expulsion by the Jews," and another 8 percent saying the refugees left due only to expulsion by the Jews. Another 41 percent said that the refugees left "due to fear and calls of leaders to leave," the traditional "Zionist narrative."
Some 46 percent believe that Israel and the Palestinians are equally responsible for the outbreak and continuation of the conflict, while 4 percent blame only the Jews. Some 43 percent primarily blame the Palestinians.
In a question about who bears responsibility for the outbreak of the 1987 intafada, 23.6 percent of respondents said it was "Mainly natural hatred towards Israel," and another 17.2 percent said it was "somewhat due to hatred." Some 32 percent responded that the 1987 intifada was caused "More or less equally due to hatred and other reasons (such as unwillingness to be controlled and harsh treatment by Israel)."
Let's not forget that there are many different kinds of Zionism, each providing its own perspective on history. The study is a reflection of that.
When historians go through historical archives, interview people, or gather any kind of evidence, they choose what is relevant and what is not. Journalists do the same and they are at their best when they are objective. But of course, journalists and historians are still human and will never be objective in everything that they do.
The first time I heard about the "conflict of narratives", it was during my high school trip to Israel. The speaker was a smart American-born historian with a best seller book about the 1967 war. I am of course talking about Michael Oren who is now the new ambassador to the US.
I believe that the Zionist narrative's greatest strength, as compared to the Arab Palestinian narrative, is that its a lot more open to discourse and debate. This of course, comes from the environment the observers live in. Anti-Zionists and critics of Israel hold the faith or nationality of their spokespersons front and center when they are Jewish or Israeli. The implication is that since some of the other side believe in their narrative, it must have merit over the other. But as my psychology teacher said, "correlation does not imply causation." I am implying that the society of many anti-Zionists (i.e. the Arab and Muslim world) is totalitarian to an extent as this report about 88% of Palestinians in Palestinian jails being held with out trial indicates. But I might fall to my own biases and correlate without looking at the causation.
I am no authority to say who is a good historian and who is not. I didn't read Oren's book on the 6 Day War but I did read his other book on America in the Middle East, "Power, Faith, and Fantasy...", a book I highly recommend.