Two notable jail breaks recently--the Mexican drug lord and the two cons in Dannemora prison. In both cases the escape route was a set of passages connecting the jail cell to the outside world. I don't know how often there are these sorts of escapes, but they've been happening at least since Dumas wrote "The Count of Monte Cristo".
It's bureaucratic inertia at work. The easy way to screw up such plans is simply to move prisoners around to different cells at unpredictable intervals. Someone can invest the time and energy and willpower to create a passage from a cell to the world only if reasonably assured that they will benefit by it--remove the assurance and they won't invest the effort. But given that prisons are bureaucracies devoted to maintaining control and order, the idea of creating uncertainty is unthinkable. (To be fair, such transfers would likely disrupt established social routines within the prison, so might well be more undesirable than an escape every x years.)