Their leadership didn't seem to know what to do and chased a few passing fads for new features, and didn't address the tech debt they had to improve the UX of their tool.
They added a wallet with Stellar Lumens when that should have been entirely separate. Git repo hosting that should have been left to Github/Gitlab. etc etc.
My opinion is that they should have focused on integration with 3rd parties like github. Plus working on tech debt and UX issues. Created lots of docs on integrating KeyBase with your internal tooling, stuff like that.
I don't think is the reason Keybase faded (although I agree that they shouldn't have chased blockchain fads). I'm pretty sure it's because they were bought by Zoom and had all of their engineering talent repurposed.
It's my personal opinion that they had lost their way before getting bought by Zoom. Mostly gut feeling from the actions and words from senior leadership.
But you're correct, Zoom's purchase was the death knell.
They added a wallet with Stellar Lumens when that should have been entirely separate. Git repo hosting that should have been left to Github/Gitlab. etc etc.
My opinion is that they should have focused on integration with 3rd parties like github. Plus working on tech debt and UX issues. Created lots of docs on integrating KeyBase with your internal tooling, stuff like that.