Except for a very few places with warfare or seriously failed states, the world is already more or less "post scarcity". Most countries already have more health problems due to obesity than mal/under-nourishment.
But wealth continues to play a role in determining social hierarchies, and as long as it does, there will be pople that see themselves as poor.
And so far, automation has contributed to making the relative differences greater than before, not smaller.
Wouldn't post-scarcity mean that most things are essentially zero-cost? And yet we still pay for food, energy, clothing, transportation, etc. Yes, goods are mass produced cheaply and tons of food is grown, but it still has a cost. It's not like being able to tell the replicator to make you an Earl Gray tea. Instead, that tea has to be grown, shipped and sold.
If you look at the number of hours an average person (worldwide average, not restricted to Detroit factory workers) must work for the same amount of food, energy, clothing and transportation, the costs have been slashed to a fraction of what they were 50 years ago.
If presented with the purchasing power of today, 50 years ago, the average person of that time would see 2019 effectively post scarcity. They would hardly be able to imagine how they would need more wealth that what we have now.
But 50 years ago, the coffee was cooked in a kettle at home, while today, people expect to buy it at Starbucks. In East Asia, most people of 50 years ago hardly ever ate meat. Today most can eat at McDonalds, but Kobe beef may still be out of reach, etc.
As long as our expectations grow faster than our income, we will feel poorer as we get richer. Today's luxery goods will be taken for granted, and new, more expensive ones will be available.
Unless social hierarchi position somehow becomes independent of wealth, some people will continue to see themselves as poor.
But wealth continues to play a role in determining social hierarchies, and as long as it does, there will be pople that see themselves as poor.
And so far, automation has contributed to making the relative differences greater than before, not smaller.