Anyhow, short answer to: "What's Happening to Reading?": it's being replaced by video content as primary source of entertainment. Main drive behind mass reading was amusement, not practicality. Now that amusement no longer requires (much) reading, the general level of literacy of the public is not exceeding that.
It's a product of many cooks and their brilliant ideas and KPIs, a social network for devs and code being the most "brilliant" of them all. For day to day dev operations is something so mediocre even Gitlab looks like the golden standard compared to Github.
And no, the problem is not "Rails" or [ insert any other tech BS to deflect the real problems ].
Too bad Phabricator is maintenance-only now https://en.m.wikipedia.org/wiki/Phabricator