I hate when the discussion devolves into putting flesh bodies into 40 hour a week boxes to repeat some repetitive task.
The truth behind job scarcity or not is supply and demand. Period. If there is no demand for yours, or someone elses labor, there is no job. No wealth redistribution will change that. The arguments behind why, though, the concentration of wealth was bad, is that the wealthy have fewer demands they want met relative to the entirety of everyone else. A more prosperous majority gnerates tremendous demand, millionaires generate limited and specific demand.
But you don't escape the reality of having a supply of something trying to meet the demand for it. There just isn't much demand for a lot of labor types, and producitivity multipliers in technology lets that demand be met with much less workforce supply, which means tremendous economic efficiency gains.