Our followup Karaoke system [1] can support more users by adding more servers, but we still have more work to do to support billions of users. Regardless, I think it's worth deploying these research prototypes to get a sense of what problems matter to users.
I used pwclip [1] for several years but I no longer believe that hash-based password managers are the best plan. Now I'm using Seal [2], which is like pass but doesn't depend on gpg.