Most likely, they would be using asterisk-based dialers to handle their customer interactions. Some of them even have 100s of seats running on Asterisk dialers. Once they realize that it is becoming difficult to run their operations, they keep adding technical and support resources to manage and maintain the open source system, for it is not built to handle such loads. The kind of skills needed include knowledge of IP networking, system administration, traditional telephony, scripting language, working with APIs,
While the dialer is open source and it comes cheap, overheads are plenty, inefficiencies are plenty and after a point, you will have nowhere to hide. While Asterisk is just an engine, what the enterprises need is the complete vehicle.
After all, a 5% increase in customer loyalty can increase profits by up to 95% and the cost of acquiring new customers is 5 to 25 times more than retaining existing ones. [Source: Harvard Business Review].