I don't think all hunter gatherers where nomads (but some agriculturalist are, or do shepherds not count), and I think I read in another book that nursing actually acts as contraceptive (Edit: I just saw that the article also mentions infanticide to keep children spaced four years apart, so true, some gruesome aspects are there).

Anyway, the point is certainly not to recommend going back to a hunter gatherer lifestyle. Although I wonder if startupping is not somewhat akin to hunting.