Besides the incandescent bulb, what primary contribution did Edison supply to the utility model?

The business model and the first working utility on a small scale.

While Thomas Alva Edison is credited with the practical incandescent light bulb, his larger contribution to the electric utility system was conceptual and foundational. He developed the entire necessary infrastructure package to commercialize the light bulb, including reliable dynamos, durable wiring, metering systems, and sockets. Crucially, he flipped the switch on the Pearl Street Station, creating the world's first commercial central power plant designed to serve a defined district of paying customers. This established the initial business template—a centralized generation point delivering metered power to a consumer base—even though the technology itself proved geographically limited.