Mostly my observations when I was doing my PhD at one of the pretty good schools (one that considers itself in the top 20, but may actually be in the top 50). I might be suffering from the selection bias as well (as I decided not to pursue an academic career), but I did see professors who had no Ph.D. students, did not publish or present and just took it easy with a minimum teaching load. I do not doubt their teaching skill, but they were doing the job of, say, a senior lecturer at 2-3 times the salary and half the workload. There were not many (maybe 10-15%), but not a single case either.

My experience was on a "pure science" / paper and pencil side. Maybe it was the fact that one does not need grants for labs, etc. that takes pressure off as well. Among the grads (at least in physics) the split between experimentals and pure would be crystal clear any weekend: the first were in the lab, second played warcraft :).