With the advance of automation and further human job loss, who is going to be left to buy anything, much less try and make a living?

Self check outs, computer banking, and driver less trucks.
The advance of technology in other industries what are the humans that are affected by this advancement supposed to do?
Are we supposed to just resort to be slaves, or work in a cubicle for the rest of our working lives?
Sorry for this question being of several parts, but it does all sorta lump together.
Here is one more with all this automation doesn’t that in itself prove the gap between the rich and poor is just getting wider with all the job loss due to automation?