They're competing for the same staff (clearly since the author has decided to return to industry), so why wouldn't you compare their pay?
However, since the supply of PhD students grossly outnumbers the number of tenure-track positions, people do end up in some kind of limbo (post-docs, non-track lecturer or adjunct positions) for a long time.
The tenured positions also don't pay as well as industry but they come with much greater freedom, more flexible balance of research vs. teaching vs. service and incredibly robust job security.