Parole points
Christianity Today has a survey article on why very few churches do prison ministry. The survey completely misses the main point. CT doesn't have comments but I just had to answer this.
Can't go to sleep! Somebody's WRONG on the Internet!
From the prison viewpoint, church or chapel serves only one purpose. Parole points. Sprucing up your 'resume' for release. Many prisoners, especially blacks, are deeply and solidly Christian, but the church in jail doesn't invite serious worship.
It's sort of like a vo-tech classroom where most of the kids are there to get Federal subsidies, not to learn. The students who genuinely want to learn are submerged beneath the noise and apathy of the subsidy-grabbers.
I suspect some of the preachers who answered CT's survey have been through this experience, which is exactly why they gave up. Can't tell for sure because the article doesn't go beyond the survey.