"if machines take over the economy, and earnings and capital are therefore increasingly concentrated in a few hands, should resources be distributed? And what, if machines are doing the work, does everybody do with their time?"

I think this is an important point; there will not be one solution to this; some of the gap will fill with misery, some with generosity and family, some with hobbies and fun, some with hedonism and self destruction and some with quiet, small lives of local interest and self respect.