Manufacturing is different from organizing events. The latter is more project oriented and is as often done that way.
Imagine the following:
In a guitar manufacturing company the team that builds the custom (electric) guitars consists of John, Tom, Dick and Harry. Tom is good with wood, Dick with paint, Harry with electronics and John assembles all the parts.
In following production schema the tasks and their personel association would always be (simplified)
1. cut wooden elements and sand these - Tom
2. paint wooden elements - Dick
3. assemble and solder electronic parts - Harry
4. assemble all parts into guitar - John
When not adding these assignments to the routing tasks, the production manager must always add these to each production run manually.
Another scenario is the case of a large team is part of a manufacturing department. In that case you would add all the theme members to the schema task, and when production run is created, the manager deletes the persons from the roster that will not work on that production run.