Surely after a few months of driving you get a pretty good sense of actual costs and revenue. Yet many drivers keep driving for much longer than a few months, even when they lease their cars.
In my experience even small-scale commercial fleets have a really bad understanding of their cost of ownership.
Cost of ownership has huge variance. A surprisingly large number of people have no idea when to do an oil or brake or battery change. Small accidents can change your cost equation dramatically. Random crap like hitting a pot hole, a hailstorm or someone scratching your car while parallel parking can trivially drain a month's salary.
It is very difficult to foresee these expenses unless you have an extremely consistent driving experience, and given that most of the drivers are not doing this professionally and don't have great numeracy skills, many will be in trouble.
Maybe they find a benefit in the relationship?