Even with the potlatch tradition someone somewhere had to produce what was given away.

True. But the tradition ensured that leaders were accumulating social wealth, not resource wealth. The fascinating thing was that the participants were producing surplus solely to re-distribute it.

This is fundamentally different from our model where surplus is converted to markers and then hoarded. Well... "invested" is the polite word.

You'd think that in a steady state economy there would be no such thing as surplus.

Plenty of surplus if one has far less people than what the local biosphere can provide.