An old adage, similar to "what came first the chicken or egg", in the business world could be applicable here, "all other functions within any company are not really required until something (product or service) is sold" - advantage sales folks. Production folks counter with, "sales people can't sell anything unless someone produces it." Almost true but you can always buy a product or service from another entity.

Food for Thought:
In reality, it takes everyone rowing the boat to contribute effectively and efficently to get it from point "A" to point "B" in a reasonable time at an acceptable cost to survive. Team work always works best and produces the best results when all functions involved are viewed as equally important.