Once you (as in you the person) have the expertise, what you need all the people for exactly? To fine-tuning you need to figure out the architecture, how to train, how to infer, pick together the dataset and then run the training (optionally setup a pipeline so the customer can run the "add more data -> train" process themselves). What in this process you need to hire so many people for?
> Why would they join you rather than founding their own company?
Same as always, in any industry, not everyone wants to lead and not everyone wants to follow.