Economy is very much real, and it's funny to see Anarchists say shit like this, can't beat the stereotype. Production and its distribution is global, you have to know what and how much to produce either via the use of markets (capitalist) or planned economies (socialist/communist).
You could previously make most things locally so these concepts didn't exist, but that's only because people were mostly living the life of a peasant, but now you have tech, advancements in medicine, and not every state has these kinds of resources.
However, the mainstream economics and its models are bullshit, the more complex people make them the more de-attached from reality they are
Yeah, apart from the voodoo magic such as finance and whatever economic models economists talk about, which when failed they use more voodoo shit to justify why.
Economy in terms of distribution and production, that's real and will exist from mercantilism to communism and maybe beyond given our globalized economy.