Quote from ssrrkk:
I think it boils down to timescales of impact to the economy. When you invent a new technology, or build a bridge or airport, you as the manufacturer or construction contractor not only made profits and employed people by doing so, bu you also created a lasting (potential) increase in the GDP. To a lesser extent one can do that by increasing efficiencies in the market. But making tangible goods usually have a longer lasting impact to the economy (other than food). For example if you make a car, the person who bought the car is now in a position to make more money and live more efficiently for at least 5 years or more (e.g., drive to work, get work further away from home to use his or her talents, save time buying groceries etc). Of course, we are overlooking environmental costs when we do that but... If all you are doing is increasing efficiencies in the market, sure that will have an impact but the minute you stop doing it, that impact is not there. This is how the entire service sector works too. The "product" itself does not have a multiplier (except for the transient effect on efficiencies), only the profits generated from it does. But that profit is usually a result of zero sum, so it doesn't add to the economy. But if you created a new technology or build lasting infrastructure, the product in that case creates a true lasting multiplier in addition to the zero-sum profits of the manufacturer / contractor.