The time when humans are being replaced by robots is already here.
Amazon does it in warehouses, waiters are going away, manufacturing, you name it. The crux is there are a billion more people in the next ten years. There will not be enough jobs for these people. Yes, yes, we already know no one gives a damn about the bushmen in the middle of nowhere, but we are talking about Americans. This push towards a service sector economy looks great on paper but sucks in reality. Nations that are not makers are not nations for long. We are declining. Our children learn nothing in schools that will be applicable to them in a meaningful way. STEM is not taught in the US. We have common core, which is a joke designed to bring everyone down to the lowest common denominator. We either start making stuff again or we fade out. Where will everyone work in a service-based economy? Fast food? These jobs are being phased out slowly, but quickly enough.
The proportion of service sector jobs increased from maybe 5% to 50% between 1800 and 1950 and is around 70% now. Your claims could have made sense two centuries ago. Having manufacturing go from 20% to 5% of jobs changes nothing.