CNC: Why do some machining plants "point out" that they don't want to make molds? Why?

Moulds are generally produced in one piece, and the processing technology and skill requirements are different from those of mechanical processing plants. Mechanical processing plants generally produce finished products directly, which belongs to mass production. Another reason for this factory may be that they are afraid of being used for mold processing and generally do not adapt to mechanical processing. Mechanical processing plants are generally more tired than mold processing and pay less. To put it bluntly, it's not that people who make molds are not skilled, the key is the right question!