Yep, many people forget GitHub was trying to be Facebook but for coders from the very start. Back in late 2000s when FB was the hottest startup everyone was trying to do "the Facebook of X" knockoffs.
Missing from all these is a social network of "our friends and adjacent social circles". And perhaps, on top of it, a service aggregating output of all the ones you listed, so as a user, I can have (for a lack of better term) "people-first" mode of interaction. By this I mean, I want it to answer the question, "what have X been up to recently?", where X is a scope I can alter - from "all my friends" to "a particular group" to "particular friend".
I.e. what Facebook used to be, before the "great social network unbundling".
