you're quite backwards, the marketing designers allow those other designers the opportunity to take the predefined numbers they're given and plug them into their autocads that spit out results. no company survives without the marketing that generates customers and allows everyone else to have their jobs.
I'm by no means dismissing marketing people, not even saying they aren't important. A good marketing group can take a company making good money and push them to the next level. I just see it the opposite way. I work for a small company that has been around for close to 60 years. We don't have a marketing group and we do well. We don't sell to the public though. We sell products to the government, boeing, lockheed, raytheon, etc. Their are many other companies out there like us (just different products/services) that don't need marketing. The way I see it is a company can't run without it's engineers/product designers but can function without marketing. Even though not marketing is a stupid business decision.