It is true that AI, robots and automation in general will eliminate jobs. One way to ease into the job shortfall is to offer paid education after high school, could be community college or job services like child care where the experience is on the job training just to sample the work experience. Require mandatory military service or community service for one year. So seeking jobs begins at age 23 or 25. Next move the retirement date 60.
Now it was stated the a minimum UBI does not need to worry about what the person is doing. That essentially will spike mental illness. Consider services or such that support satisfaction but does not require producing physical objects.
By the way what happens when the life of car exceeds 20 years and self driving all result in production of cars dropping by 75%. Does that suggest you can support other consumption. Not sure how you are drawing the consumption line. In short I don’t think the proposal is well thought out. It is true that conventional jobs will decline, just like farm jobs declined by 95% from farm automation.