Oh, we know about it. 😅 It's actually agonizing because at the fall Medium staff retreat we had a hackathon and the project I worked on was a publication directory. Exactly this thing that John made, but with a more filters and sorting options and our full publication database with all 14k pubs represented.
It's also my job this winter to write a product brief about why we NEED to make the publication directory ASAP... in part because without one, users create their own workarounds, which can cause a lot of confusion.
(For instance, there are publications listed as nominators in this directory that aren't actually in the Boost Nomination Pilot and don't have nomination powers. I run the program, so I know those pubs inside and out.)
Ultimately, Medium is a small company (there are only 80 of us) and we just don’t have the resources to do all the things we want to do. A publication directory is something we’ve been talking about for over a year, and we just haven’t had the company bandwidth to get it done. It’s frustrating.