Keybase packed together many different technologies in one place. I don't think any of us who moved to Keybase had delusions that it would be around forever. But it's an amazingly comprehensive suite for its small scope and the open source product that replaces it will only exist because Keybase existed.

If the writing is placed on the wall (the marker cap is open right now) then replacing each of Keybase's features with existing technologies won't be difficult -- just time consuming, which is why they have market fit.