Keyoxide's developer has gotten some grants to really beef it up. One of the things Keybase really shines at is documentation, it makes a lot of GPG things pretty stress-free to deal with, and Keyoxide has room to improve on the user experience, polish, and documentation side.

But since Keyoxide doesn't depend on a central authority to manage proofs, it is definitively going to be the future in this space. Nobody can really kill it.