I think the overwhelming issue economics gets wrong is treating money as both medium of exchange and store of value.
For example, blood is a medium, while fat is a store. Roads are a medium, while parking lots are a store.
Since money largely functions as a contract, with one side an asset and the other a debt, creating the asset requires similar amounts of debt. Which largely explains why our entire world is drowning in debt, while supposedly trusting the financial system to store value, for our individual futures.
I try going into that somewhat here;
So the other side of your question, of what people will spend money on, is what people will be willing to do, in order to acquire that money.
We are goal oriented creatures and currently money is the signal we try extracting from the noise of the economy and society, yet as the medium which enables mass societies to function, it does have to circulate, not be drained off. Often to be used to leverage even more value out of the system and consequently creating a metastatic disaster, as money is transformed from a tool to a god. As those most willing to be most focused on the acquisition of it, rather than the betterment of society, are the ones in control.
It has become a very destructive feedback loop, for which the field of Economics does bear significant responsibility.
