Making it requires that the makers stay in the same place for a large fraction of the year. Furthermore, if they are forced to leave for any reason, all the effort they have expended so far is wasted and they probably can't try again until next year.
That's a relevant feature for figuring out the consequences of depending on grain production. I'm not sure it's a relevant feature for the purposes of deciding why growing grains became so popular.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
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2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
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