That's not the way technological advancement works. We may all have to change jobs but computer driven machines will simply provide humans will a different array of things they might accomplish...not replace them.
Think of the way in the industrial revolution created millions of jobs. They weren't always attractive jobs but they paid more than farming at the time.
This was the beginning of the creation of the middle class.
Nowadays our jobs are cleaner and more analytical and creative. They can still be stifling, but they are a step forward.
But what about teaching jobs, from K-1 through to university level, or jobs in sales, managing,accounting, marketing and product design? How would people who specialized their whole lives for work in those fields be able to find alternative work in the automated age? i don’t see how they would - and in these job areas alone we are talking millions upon millions of Americans in addition to currently unemployed Americans.