There is ONE very important factor that must not be forgotten - the environment.

Not everyone adopted farming around the world for the same reasons and at the same time. The question why some did was, I strongly believe, almost entirely environmental. It is possible that people settled first where conditions (abundant supplies) were excellent, then the areas became occupied and organized (like Salisbury Plain in the Mesolithic to mention a familiar example), and finally population growth was so rapid that food became scarce.

Also, what I mentioned at the end of the first post about the excess of salt is true. At some stage in prehistory, an excess of salt in the sea decimated the population of shellfish on the coasts, which may have forced people to join the farming bandwagon.