Rhetoric, and "Lower Cost"

What is the actual economic benefit of lowered cost in a world --- we could say "environment" --- of trade? What is the benefit of lowered cost, as an analytical stand-alone entity or concept, in the trade-based economy? (Are there other kinds? Probably there are. "The economy" is the trade-world.)
     In the trade-world money circulates. It is because of this that one persons' cost is just another person's income. Eventually all the money in an economy has to be spent, even if we frequently see persons trying to behave in the opposite way. (i.e. they want to "lower their costs")
     In the long run money is spent (, or we can say "circulated").
     Businessmen generally try to make money (in order) to increase their stash. They "make money" by taking in more than they pay out. They make money means: they acquire it. Yet the money you make has to be spent, for it to do anyone any good. Otherwise, what's the point? To keep it in shoeboxes? At the end of the day you will have paid out what you have taken in ---- just that. This indicates to me that "Lowering costs" is micro rather than macro. One the macro level we want increase. There is no differentiation to be made here, between "cost" and "income" (or however you smarites want to put that ---- the word "cost" seemed easy to arrive at, and I guess you can yse "profit" for "income" if you want). The only difference, then, would be on the "micro" level. A neutral trade entity, such as a person, or a company, and "agent" in the trade world, does not cause us to privilege either "cost" or "money made." It is the same thing.
     It does not matter (and this is a separate point, it appears) whether the neutral agent, or economic "player" is in the economy or the whole economy (or anything in-between).
     Our subjective, or culturally stated view, is that of increase. We want something to increase, right? Then what "should" increase? Wealth? Something like that, right? We want more products, then? We need more stuff? Not really.    
     WHat we really want to increase is something more like our quality of life. We think we do that by increasing our income. Then, the issue is that of how we can usefully increase  ...something.