Well, any definition of “capitalism” that includes the economic system of North Korea or Cuba is a definition that doesn’t make any sense.
There’s already a term that describes what I think you’re getting at, which is “Industrialism”. That is, communist Soviet Union, fascist Germany and Italy, democratic United States, Britain and France, and imperial Japan were all industrial powers, despite having very different economic and political organization.
Capitalism is defined as a system with private ownership of capital goods. If the state owns all capital goods, you don’t have capitalism, you have socialism.
So a postcapitalist economy would be one without private ownership of capital goods. And it seems to me that if capital goods become so cheap that pretty much anyone can have pretty much anything manufactured pretty much any time, there’s no benefit to accumulating capital goods. There aren’t any factory owners if there are no factories any more.
There will always be some types of goods and services that will be scarce–they aren’t making any more land, for instance. But note that while land in downtown Manhattan is incredibly scarce, there are millions and millions of acres in northern Canada, or the western United States. If you just want “land”, you can buy a couple of acres in the middle of nowhere for very little.
But if fabrication and manufacturing become dirt cheap (ie, you shovel dirt in one end of the fabricator, and finished goods come out the other), then that breaks the need for humans to be crammed together into cities. If a typical person can live a middle class lifestyle isolated in the middle of Baffin Island, and they produce everything they need from their personal fabricators (including more fabricators as needed), then we’re talking about a radically different sort of economy.
There’s going to be some sort of need for exchange of goods and services, but on a completely different scale than we are used to here in the 21st century. I look around my house and it’s crammed full of manufactured goods produced in factories from all over the world, all purchased with money I made by working to produce goods and services for other people. There are a few goods that were created by me personally, or by family members, but that’s a tiny fraction of the total goods in my house.
Now imagine a different scenario. If I want a chair today, I go down to the furniture store and I buy one made in a factory. Or I could collect some wood and make one myself, but it would take me only a few hours of labor at my regular job to accumulate enough money to purchase a really nice chair, while it would take many more hours to produce that nice chair on my own. In many cases it costs more to purchase the raw materials for a product than it does to purchase the finished product. So while I always have the ability to opt out of the industrial economic system, I almost never do because it’s almost always cheaper and easier for me to opt in.
In a post capitalist or post industrial economy that wouldn’t be the case. Personal manufacture will be cheaper and easier and more convenient than to exchange my personal labor for goods created by someone else.