It's interesting how the article is written in the past tense, and the Society (presumably) no longer exists, but there's nothing in the article about the decline and fall. The history just basically ends in the 1950s, at the height (?) of the society's cultural relevance. Most articles that are this well sourced and detailed include at least a bit of "late history", but not here. I guess people just stopped writing about it so there are no sources that chronicle how it petered out?
I also thought that and was surprised they never moved to the digital age, at least in a meaningful way.
It's really cool seeing how people connected with strangers from all over the place before the Internet. Also makes me wonder how many interesting uses of real estate like Home and Garden there are today in populated areas (34th st in Manhattan, etc.).