Whether it's a factory assembly line, or a service assembly line, it is still an assembly line to produce a product or service or service/product. To me, it is all factory work. Either assembling a product or delivering the product to the customer in exchange for money, all pre-programmed, repetitive actions.
In my life, I have worked flipping burgers (the fast-food service factory or assembly line), secretary (service assembly line/factory), admin assist (service assembly line/factory), project manager (product assembly line/factory), marketing communications manager (brochure and data sheet assembly line/factory), documentation specialist (service/product assembly line/factory), budget specialists (service assembly line/factory), etc.
Right now, after very expensive and intensive training, I work in a hospital laboratory, a service assembly line/factory. Specimens come in batches, we process them, run tests, review the results against diagnosis and patient history to ensure they make sense, and then report results (unless they don't make sense, in which case we investigate). We maintain the machines that do the tests, calibrating and running QC on them, replenish and replace chemicals, manually clean various parts, run automated clean cycles, etc. It is a health care factory that provides a service/product. The product is the test result. The service is collection of the specimen and delivery of the test result.
The pay is higher in the laboratory assembly line/factory than it is assembling hamburger products or running the cash register at the burger service/product factory. But not even close to high enough to justify the education needed to do it.