On the other hand, "successful arrival of passengers at their chosen destination" doesn't say much either. That's the absolute bare minimum. It's like saying that the product of airplanes is to not crash. Technically true, but meaningless on its own. "Passenger arrives at destination" is also nothing more than a requirement which describes the service - and that could even be met by sending me a taxi!

You're absolutely right that a fancy timetable with all its trains getting cancelled is worthless, but so is a train service which doesn't provide useful routes, which is delayed by hours, and which only runs once a week. When I am looking into commute options, they are selling me the timetable: if they don't provide meaningful transit options, they aren't getting my ass home anyways.

The product they are selling is the promise of a convenient transit option - which is presented in the form of a timetable, and delivered in the form of a train. And yes, if they can't reliably deliver on that transit option by not getting me from A to B as promised, I will be asking my money back.