I, for one, welcome our new robot overlords.
Distopian robot futures aside, automation that actually results in increased productivity at reduced price is a positive development. An automated job does not require a human that has a family, a car, a commute, a need for food and housing, or a seat at a restaurant, movie or concert. Thus, they will not occupy the same niche as people, and will not compete directly in living.
Jobs for people is the real problem. Despite long range hypotheses on how economies might react, the basic supply vs demand balance is always and immediately applicable.
What effects labor supply? That is easy. The number of people.
But the demand part of the equation is just as important. Some would say that growth is a solution, but growth is never guaranteed, sometimes there is recession. And growth that does not create jobs does not help. If employment is desired, growth must include real jobs. We need job growth, which increases labor demand.
With regard to demand, there are other arbitrary factors to consider. The 40 hour workweek is an arbitrary parameter that could be adjusted. A 32 hour workweek as as a default could increase demand for individual laborers, assuming that many businesses would be open more than 40 hours a week. Reducing the workweek could create more jobs, possibly offsetting those lost to automation.