No, because then it's what's optimized for. It's like if you run a hospital "like a business" -- it becomes optimized for making money at the expense of patient care.
It's not like a hospital at all -- not that many hospitals couldn't benefit from being run better.
The revenue of a train line is proportional to passengers served and forms a baseline for the total value the passengers received from the service. There's no problems with stuff like quality of passenger care.