"If agriculture was a last-resort method, why didn't smaller fractions splinter off from the groups and continue their hunter-gatherer lifestyle?"
I think he mentions implicitly that agriculture cannibalizes resources that were once diverse and auto-regenerative, in the comment about hunter-gatherers being forced into some of the worst real-estate in the world today.
There's a secondary point that heaps of knowledge about the natural world have been lost, since even the modern, technologically advanced life sciences of today do not reconstitute the "working knowledge" that humans had of how to live off of wild plants and animals for food, medicine, and shelter.
Current events certainly bolster Diamond's argument in some ways. Look at the speculation/agriculture-driven burning of the world's rainforests, for example, for the conversion of mass tracts of biologically diverse (and productive) land into monocultures of diminishing returns.
I think he mentions implicitly that agriculture cannibalizes resources that were once diverse and auto-regenerative, in the comment about hunter-gatherers being forced into some of the worst real-estate in the world today.
There's a secondary point that heaps of knowledge about the natural world have been lost, since even the modern, technologically advanced life sciences of today do not reconstitute the "working knowledge" that humans had of how to live off of wild plants and animals for food, medicine, and shelter.
Current events certainly bolster Diamond's argument in some ways. Look at the speculation/agriculture-driven burning of the world's rainforests, for example, for the conversion of mass tracts of biologically diverse (and productive) land into monocultures of diminishing returns.