In my view, we should be focusing on the overall net worth of the state, not just the national debt. The proper objective of fiscal policy should be a return to a situation where the state has a significant positive net worth. Of course the reduction of the national debt would contribute to this end, but it is only one side of the equation. The other side is the accumulation of state assets. By holding capital and by sharing in the fruits of technological developments, the state can use the resulting revenue to promote a less unequal society. This is all the more important, given the earlier analysis of the economic forces driving the distribution of income. To the question, who owns the robots? the answer should be that, in part, they belong to us all.
this resonates with the idea of "welcomed nationalisation" that Toby brought up - that you should innovate with the hope of eventually having your creation nationalised, with the profits going to everyone and not just yourself; that it should be something you celebrate and strive towards, because what is a more worthy goal than actually making the world (or at least your subdivision of it) a better place?