I wonder how much service sector growth is in low-paying jobs (?).

Usually what happens with new manufacturing processes is that the luxury market retrieves older craftsmanship, so there may be a small market for those types of 'old-fashioned' goods, like fountain pens and mechanical watches today. I think the biggest challenge in the winner-take-all platform capitalist era will be finding buyers. There has to be a thriving (and achievable for the lower classes) middle class to keep all this going.