Commercial models are people filmed or photographed for ads. They are also found in live commercial and web media. Anyone you see on television commercials is a commercial model. Commercial Models who earn good money. With that pay comes the expectation they can execute. There is a big crew working on the set. That crew is being paid as well. The longer a commercial shoot takes, the more it costs.
Important to note, commercial opportunities come along less often. A model must be cast by a casting director. They must attend go-sees. They may read lines for the client, casting director and production team for 2 minutes or less. In the end their persistence pays off with a high paying booking or its back to the drawing board.