The (vast?) majority of pre-industrial tribes I remember studying in anthropology live in very fertile areas like the Amazon, Pacific islands, and the mountainous jungles of central Africa or Papua New Guinea. These areas can support small scale agriculture but for various reasons are impractical to exploit economically.
Anthropologists have gone to great lengths to study tribes that have had little to no interaction with the outside world so our understanding of their quality of life isn't as biased as you'd think.