You know what else is a cost center? Engineering. It's perceived as a massive step up from Call Center or Customer Support or QA but it's just marginally closer to revenue generation than the sales reps and can suffer many the same issues.
At a previous company I managed to end up doing my software development work under a Sales title, so I could get the quota and commissions that would come with it. All of a sudden I was earning a percentage of revenue every time a customer bought the software I wrote, winning recognition from the CEO, going to Presidents Club, etc. and total comp basically doubled. Doing exactly the same job under Engineering in previous years won me maybe a few thousand dollar bonus, or one year a gift card for dinner.
Somehow companies don't realize that you need everyone working as team to hit that revenue number at the end of the year, and every member of that team is doing essential work. You can have Customer Support rockstars, just like you can have Engineering and Sales rockstars. It's just that the Sales rockstars are trivially easy to measure (bookings) and so much easier to reward. I have yet to read about a compelling solution to this, because a low-base / high-commission model is proven to attract and incentivize talented reps and drive out the low performers, and there just isn't an equivalent process you can apply in the cost centers.
Not every employee wants or needs to be on variable comp, but the way we manage and reward employees is often very much dependent on how closely they are to driving revenue. I would be interested in case studies on companies that have managed to Think Differently on this, and I don't just mean a "profit sharing" plan.