Edit: Changed title to be more accurate.
Also here is the summary from Wikipedia on what Post-scarcity means:
Post-scarcity is a theoretical economic situation in which most goods can be produced in great abundance with minimal human labor needed, so that they become available to all very cheaply or even freely. Post-scarcity does not mean that scarcity has been eliminated for all goods and services but that all people can easily have their basic survival needs met along with some significant proportion of their desires for goods and services. Writers on the topic often emphasize that some commodities will remain scarce in a post-scarcity society.
Is someone with the power to grant promotions or dock pay not a representative of the owner, who has all those powers? Sure if the workers all own shares then they are also owners, but hiring and firing are actions performed by owners or their representatives. Workers perform labor.
You’re off.
In Capitalism, we refer to the managerial class as Labor Aristocrats, they often side with Capitalists to keep their lifestyle but are ultimately still laborers and not owners.
In Socialism, a democratically accountable manager or HR representative is just that, democratically accountable. Even though they are involved in managing, if they do a bad job, the Workers can oust them, or even do away with the position entirely.
Ownership entirely changes the power imbalance.