The Zionist project was very successful indeed. By 1948 the embryo nation was strong enough to create a state. Israel was born.

When one builds a house, one needs scaffolding. When the building is finished, the scaffolding is removed.

But political ideas and structures don't die easily. The human mind is lazy and apprehensive, and clings to familiar ideas, long after they have become obsolete. Also, political and material interests become vested in the idea and resist change.

Thus "Zionism" continued to exist after its aim had already been achieved. The scaffolding became superfluous, indeed obstructive.