It’ll probably change to something else if we can attain post-scarcity (or at least very low scarcity). It’s hard to say what that will be.

Someone correct me if I’m wrong, but it’s not like capitalism just came out of nowhere. Economists didn’t go to the economics factory and design capitalism, it was the progression of other economic systems and the result of various societal changes. Someone in the century before what we now call capitalism came about probably had no idea that it was coming, and I’m sure the average person in Adam Smith’s time simply knew it as the way the world worked without putting much of a title on it.