That's an interesting read, thanks. So based on the assumptions in the piece, I can see how it's technically possible. But it's still not practical.

And I think this is the heart of the discussion: just because it's technically doable doesn't mean people will want to do it that way. If all the UX improvements bitcoin needs to scale ultimately come down to "someone can spend and receive money using a password" but if you lose that password your money is all gone... most people do not want that.