Centrex could not compete in price or capability, so Centrex was presumed dead. PBXs continued their dominance in the market with advances in their features and capabilities. Divestiture gave Centrex a shot in the arm which sparked the development of features and capabilities on par with PBXs. Competition and the digital upgrade of telephone switching offices are largely credited with this resurgence. Maintenance is covered automatically for as long as you subscribe to Centrex.
Feature offerings are sometimes limited and governed by state regulators.
Management of system may be delayed due to batch processing. Depth of system management may be restricted. Features are incremental costs for packages or individual features. Costs are monthly recurring for the life of the system. Telephone options are numerous and standards based, from basic to digital.