Answer: That era and lifestyle was really defined by the rise and wane in the demand for fur products, particularly hats.
Explanation: The economic factor of life affect everyone in the same way. When demand for a product increases it motivated efforts for further supply. Scarcity of a resource will also drive efforts to secure more of it. Thus, the entire development of the "Mountain Man" was based initially on a particular market supply-demand issue.
Everything else that they are known for is primarily a result of simply surviving in order to fill their particular market niche. In daily life they often "lived off the land", which meant a cycle of deprivation and plenty.
