(briefly busting out grammar-police) "There's a running subplot about ancient family conflicts over a stolen recipe for a legendary beer recipe..."
Really, Bob? I think you need to fire your editor-- that is such an awkward and inept construction...
Anyway, doffing that cap, excellent article, but I feel compelled to point something out: the reason the Thin Man had so much drinking in it is because it was made/released the year after Prohibition was repealed, and thus it was still widely considered to be really cool to overindulge. (Or should I say 'hip'? What superlatives did they use in the '20s and '30s, anyway?)
Man, if I had a time machine, I would totally go back to the Roaring '20s, visit a Speakeasy, and hook up with a flapper!
EDIT: oh, and in regards to the psychological/sociological aspects in regards to ancestry, while what AcacianLeaves said is a good start, but to dig a little deeper, you may want to investigate Psychology and Motivational Theory, specifically 'Need for Affiliation'. Not really in my wheelhouse because my studies were on Cognitive and Abnormal psych, but I figured I could at least throw those out there for those of you who are interested in why people invest so much importance into ancestry.