Ideally, a new product or service, which would make you and your company truckloads of money, would be developed step-by-step across many different departments, each of which has a certain specialty. People suited to one would perform terribly in another, but that's okay, because cooperation and distribution of labor are what civilization is all about.
First, the marketing department determines what the customers need and would pay money to solve. A problem they have. Let's say, as an example, that their feet are cold.
Next, the marketing department explains this to the engineering department. Puzzling through this, they come up with solutions of varying degrees of practicality. Let's say that "battery powered socks" are the best design we get from this.
The industrial design department takes the most practical invention of the engineering department, and remakes it into something artistic and eye-catching. The "battery powered socks" now have an elegant place for the battery, a cotton-like texture that conceals the internal wiring, and resembles an ordinary sock yet keeps your feet much much warmer.
Industrial design passes this on to manufacturing, who make a factory that cranks out ten quadrillion or so, depending on what marketing thought they could sell, of them, packs them, and ships them.
Sales gets the product, produces commercials with help from marketing, and convinces people that its worth trading money to get battery-powered socks, and that your warm feet are well worth what one would pay. This makes the company all the money it needs to stay afloat, pay everyone, keep the buildings operating, and a little extra profit to hand back to the shareholders, who expect this.
Accounting tracks the money flows, and raises the alarm if any spending gets out of hand.
Executive makes sure none of these departments gets side tracked, fights with themselves or the other departments,
Now, any one link by itself would fail. Marketing or sales alone would have no product to sell. (Except maybe loans, but the financial industry is kind of tapped out right now.) Engineering alone would design functional, but inelegant products, and have no clue of how to convince people to trade money for them. Industrial design could make stuff, but it would be lower quality without the pure-engineering department. Manufacturing alone could only make things they had made before. Accounting alone could tell how much money they had, but it would only dwindle, because there would be nothing to sell, and executives alone....would be Enron. Except with no oil money. Oh, and with no accounting, one unscrupulous person could write themselves huge checks and no one would notice, and with no Executives, the departments would likely quarrel themselves to death. No manufacturing department means everything gets made by hand, which means less of it and it costs way more. Way way more. No sales department means no money, and goodbye company.
And a person well suited to one would work out terribly in another. A marketer thrown into accounting would die of loneliness and boredom. An accountant thrown into sales would bore the customer to death. There's some overlap in engineering, industrial design, and manufacturing, though an industrial designer has to be the most artistic, the engineer has to be the most scientific, and the manufacturer has to be the most practical.