One possible explanation, from Andrea Matranga (working paper here) is that there was an increase in the earth's axial tilt around 10,000 years ago. This caused an increase in seasonality, attenuating the differences between summer and winter. This was most relevant for those areas of the world where a nomadic hunter-gatherer lifestyle was already a marginal proposition. For those areas, the value of accumulation and storage as a method of survival increased, since the plausibility of seasonal migration as a strategy decreased. Storage increased the value of staying within a narrower area, which in turn led to the increased appeal of sedentarism, storage, agriculture, and eventually "human history." Once sedentarism takes over, the value of switching back to nomadism becomes very low. Places where seasonal migration was still viable do not see the same shift towards agriculture.

I don't think the theory quite has enough traction on Meso- and South America, neither of which quite fit the model. (Earlier versions of the paper had a second condition, wherein long-range seasonal migration was not as necessary in areas with many nearby ecological zones created by rugged vertical terrain, but this seems to have vanished from the most recent version.) But the increase in seasonality is at least one plausible thing that changed around 10,000 years ago that could help answer the question of why everywhere adopts agriculture at the "same time," (from a super long run perspective) after such a long period without it.