erators, telephone companies, and cellular wireless carriers will compete actively for different aggregations of telecom services, but that no one platform will likely be the beneficiary of convergence to the extent that it leaves the others at a severe disadvantage. While the technological joint economies across all services may not be large enough to induce the convergence of all major communications ser- vices, the joint economies in marketing are likely to doom entrants who offer only a limited array of services. Subscriber switching costs for existing services are substantial, and customers must be persuaded by expensive marketing campaigns to abandon their current service for a new offering that is often similar if not identical to the service they currently have. The obvious solution is to spread these marketing costs across several services by offering the potential subscriber a bundle of services. Without such a bun- dled offering, many CLECs have simply been unable to cover their start- up costs, which include very large marketing outlays. A Look Back and a Look Forward Thus single-service companies are likely to have an increasingly difficult time competing with the incumbent telephone companies and cable com- panies. As the Bell companies move to expand their packages with their own wireless services, the single-service voice carriers will find it even more difficult to amortize their operating costs. Competition's Effect on Revenue Growth Despite widespread optimistic views of the likely effects of the Internet on telecommunications, the past eight years have witnessed remarkably little growth in telecom revenues. Since 1996 the wireless carriers and cable tele- vision companies, the two largely unregulated groups of carriers, have expe- rienced annual revenue growth of 19 percent and 9 percent, respectively (see table 10-1). By contrast, wireline telephone carriers have registered a slight decline in revenues, which is now accelerating. The reason for this disparity in growth is aggressive price com