Not sure how the use of adjuncts figures into this, except as a cost-cutting move by colleges. Adjunct salaries are usually a pittance, but they aren’t counted in surveys of faculty salaries which are based on full-time salaries at the assistant professor, associate professor, and full professor levels. Those salaries have been stagnant. If anything, the increasingly widespread use of adjuncts would tend to put downward pressure on the salaries of full-time tenure-track faculty because the supply of qualified people eager to fill those jobs far exceeds the number of available entry-level positions, and to some extent it also dampens demand for lateral transfers. Bottom line: faculty haven’t been the beneficiaries of rising college costs.