What about when we reach The Singularity? When technology advances at an exponentially infinite speed that it moves too fast for humans (without genetic modification) to comprehend.
Indeed, this would be a time where there would be more than enough abundance for every being to potentially be as wealthy as the next - No pie, unlimited wealth.

As stated, wealth is subjective.

Humans simply do not understand enough of the universe to conclude what is limited and what is not.
Imagine if you will, parallel universes. Or just about any other theorized possibilities, that work in our favor.  
The more we know, the more we realize how much we don't know

Literally, entire novels could/have(?) been written by philosophers on the subject of wealth.