The subject is decentralization. There’s a huge value in curation and specific communities. You don’t go to r/all to read about emacs or bash. Instead you go to r/emacs and r/bash. Even those “awesome $thing” list are better than going through pages of GitHub search results.

r/emacs and r/bash are all communities on a centralized service that you can search using a single interface. That is an inaccurate comparison. Meanwhile, I didn't say that a common index has to be centralized.