Hi Tim, it's difficult to speculate if indeed machines can or will replace us. Graeber astutely argues that it just isn't possible. While technology makes certain forms of labor more effective, it also makes other forms inefficient. His object is particularly care labor. Interestingly, your views are exactly like Graeber's.
I certainly agree that we need to rethink how we measure value. I am utterly disgusted by how things are now. Graeber's solution is to shift our method to measure value from "production" to "care." I'm inclined to support his idea.
I'm not entirely opposed to UBI, though. I'm thinking if there's other more palatable alternatives. I'm in line with what you have in mind when it comes to the end goal.