“Post-scarcity”, “Post-economic”, and “Post-capitalist” are meant to convey a fundamental shift in the principles of human action, wrought by technological advancement. In reality, they are just cute linguistic hyperbole.
There is no change in wealth that can ever alter the basic science of economics. (In the Smithian and Mengerian tradition, not any of this modern macro math vodoo stuff). Scarcity is a necessary attribute of reality, inseparable from the laws of identity and non-contradiction. A is A; not-A is not A. No matter how many zero-price widgets you have access to, every time you choose one, you forgo something else.
Choice implies scarcity and is impossible without it. To choose one thing is to not choose something else. The thing not chosen is the cost of the thing chosen. Everything has a cost.
This doesn’t mean technological progress can’t radically alter the things we choose and the margins on which decisions are made. Sending information to someone far away was once very resource intensive in time, horses, etc. Automobiles and planes brought it down exponentially. Telegraphs and the internet make communication almost instantaneous for almost zero energy. This doesn’t mean the transmission of information is exempt from scarcity, hence economic logic. It only changes the costs, dropping one resource to near zero, while introducing previously unknown costs elsewhere.
Take email. It’s almost instant and almost zero price. But this doesn’t mean every human with internet access has all information from all other humans frictionlessly in their brain. There is a high cost to sifting through the hundreds of emails that come to me every day. To consume this “free” information is quite costly. I must forgo other activities and fill up mental space that could be utilized for other tasks. I must choose, weigh costs and benefits according to my subjective preferences, adjusting when supply and demand shift. I must economize.
Changes in price do not change the laws of economics. Neither do changes in preference curves, supply, or demand. Even if you could cheat death, you could not cheat the laws of economics. An infinite life still requires choice and trade-offs in each individual moment. Economics is eternal.
An age of abundant information, food, medicine, or any other resource will radically alter the way we experience life. But every one of those experiences is still better understood with rational choice theory and the basic economic principles of scarcity, price, supply, and demand.
We sacrifice the most valuable analytical tool in all the human sciences if we let ourselves be fooled by abundance into thinking it alters the basic logic of human action.