"Settled agriculture replaced hunting and gathering slowly; the transition was neither immediate, nor obvious." Doesn't that seem counterintuitive?
See Chapter 6 of Gun, Germs, and Steel by Jared Diamond.
It would only be counterintuitive if one imagines the shift to agriculture as the result of an "invention" or a "discovery," a notion that Diamond specifically refutes in Chapter 6 of Guns, Germs, and Steel. People began to practice rudimentary agriculture without really thinking about what the consequences would be, or recognizing that they were adopting a new way of life.
Diamond argues against a "dichotomy...between food managers between food producers as active managers of their land and hunter-gatherers as mere collectors of the land's wild produce." This is significant because many of the activities of hunter-gatherers strongly resembled agriculture. Additionally, many people "simultaneously collected wild foods and raised cultivated ones." Over time, the process of collecting gave way to cultivation, but the process was "piecemeal," because it "evolved as a result of many separate decisions about allocating time and effort."
What's more, these decisions were almost certainly informed by each other. As one man began to cultivate foods, others may have been persuaded to do so as well. So the process was slow, and seems not to have involved a wholesale, conscious decision to abandon hunting and gathering as a lifestyle at any one point in time. Rather agriculture gradually replaced other forms of food production, and it did so at different rates in different places.
Source: Jared Diamond, Guns, Germs, and Steel: The Fates of Human Societies (New York: W.W. Norton and Company, 1999), 104-113.