Humans in societies have been chemically altering their moods since we discovered mood-altering chemicals. Stress occurs inside and outside civilized workforces, and people take measures to mitigate stress. The real question is: what are the side-effects and how do we mitigate them?
(Not to imply that we shouldn't also look into options for de-stressing the American worker, since benefit there can scale significantly. But we do ourselves a disservice by imagining we're the first generation to have an entire culture habitually consuming a physiology-tweaking chemical cocktail)