The more general excuse for overworking bankers is to limit the number of people accountable for a particular project, meaning no sharing of workload even when it would be efficient to do so.
The question become then, why do clients allow them to get away with it? Do they satisfy their clients to such an extent that they don't care about bloated costs or do the clients just not know?
Edit: changed metal to mettle >_<" thanks
And for a client, the deadline is more important than the money sometimes. I mean, when you see what these firms bill, it's obviously money is no object for the customer... because damn.
If the job market keeps worsening and huge unemployment/underemployment/unpaid work becomes The New Normal, it will become time to have a hard conversation about hard caps on working hours as a means to improve quality of life for the workers and provide more jobs to the non-workers. You want to put in 100 hours? You'd better be co-owner.