Thank you for your forbearance.
It is a risky endeavour to take issue with you, but, in this case, I will.
"In fact, wasn't the turning point the 1930s, when the revolutionary movements of post-WW1 and the 20s (which didn't just involve a few!) had failed and the rise of anti-semitic movements including Nazism quite understandably pushed the majority of Europe's Jews decisively into the Zionist camp?"
However, in order to understand the present, and work for the future, a fairly accurate picture of how we got here, successes and blemishes, is necessary.
So no, it wasn't. Zionism was called thus in self-definition as opposed to Uganda-ism and Argentina-ism and anywhere but here-ism. Its background was conditions in Russia and the Ukraine in the 1880's, when the Jewish people broke under the horrors of life there. It was always a small minority movement, hopelessly romantic and physically doable only by very young, fit idealistic youngsters. Herzl's contribution (late 1890's) was to turn a romantic beyond-the-fringe thread into a modern political fringe movement. And that he could only do by (reluctantly and against strong opposition) bringing in some representatives of the religious stream.
Zionism never appealed to the main body of European Jewry. In general, the more religiously committed a person or community was, the less Zionism appealed. The more observant, the more anti-Zionist. To no small extent, that is still true today. America was the ideal of choice.
It is true that this writer or that intellectual noted something about the Arabs of the Levant, but the main appeal, thought and energy of these youngsters was a total rejection of the life-style of Eastern European Jewry. They were rebuilding themselves.
Politically, the idealogical framework of Zionism and many of its institutions were in place by the early 20's. It was enormously influenced by the various socialist and nationalist currents of the early years of the century. (Historical aside: to the extent that some kibbutznikim even went back to the Ukraine to set up kibbutzim there. And of course they failed, fatally).
The small dribble of immigrants that came in up to the middle 30's came to and were absorbed into an already vibrant complete society. The middle to late 30's immigrants added a different middle class / middle European colour to the mosaic ("mosaic" joke - ha ha), but by then it was a done deal. They were not Zionists, just refugees running in panic and desperation to anywhere that would take them. They whole enterprise was so desperate that the "yishuv" accepted the British recommendations of the Peel report. A country about the size of Aberystwyth! Even Jabotinsky accepted it!