In a previous workplace we had a very capable part-time instructor. This fellow was never converted to a full-time position (eventually they got fed up and left

In a previous workplace we had a very capable part-time instructor. This fellow was never converted to a full-time position (eventually they got fed up and left); instead management kept recruiting externally for the full-time instructor position. They went through 3 or 4 people in as many years because the new recruits were glaringly incompetent. They were, however, innocuous and unthreatening. So far, no consequences for the departmental chair.