I think if there are you can't really call it one. America is the richest country on Earth so if it's just about how you theoretically could have a society free of want if you totally reconfigured who has what then I guess we're on the cusp too! Great news!
I genuinely have no idea what you think a post-scarcity society is.
Where society has enough for all and attempt to allocate it in a way that all gets what they need.
Japan is about as close to that as exists. Yes, people fall though the cracks, but the same will happen in post-scarcity society. People will refuse to live by society's rules so they won't get their universal income, or they will have mental illness and unable to arrange their life to avoid suffering.
That isn't dissimilar to Japan. No one is staving to death, people get basic healthcare (mostly), but there are still people who society fails - and it isn't a lack of resources that causes that in Japan.
No one - least of all me - is arguing that there aren't poor people.
My point is that this is what a predecessor to a post-scarcity society could look like.
Do you think there won't be poor people in a post-scarcity society? Or there won't be people who fall though the cracks in that society?