As an academic (but not in those fields), let me offer the following: Some of them believe that the only way to avoid being a failure is to work at a universit

As an academic (but not in those fields), let me offer the following: Some of them believe that the only way to avoid being a failure is to work at a university. Some of them believe non-academic work is worse than what they are doing already. Some of them only want to live in their current town and this lets them do it. Some of them have difficulty changing fields. Having a graduate degree, especially a PhD, in a humanities field can make it hard to get a job in another field. A few of them are just not suited to doing other work. Most employers simply wouldn't want to hire them.