To what extent is the global economy based on "futures"?

Futures is not an imaginary world. Nor are they a speculation of what is going to happen in the future. It is simply put, a derivative instrument that provides a mechanism to transfer risk to another party and therefore fix the future price of an instrument. Futures exist on all instruments such as debt, equity, currency or even commodities.

The global economy is definitely not based on futures. In fact, it would be an interesting study to see whether spot price changes and movements lead or lag the future price changes and movements.

Despite that, the statement 'real world' cannot catch up with the imaginary world of futures can never exist in equilibrium as otherwise, an arbitrage exists by which one can go long on spot, bear the cost of funds and go short on high priced futures.