One’s willingness to stick around determines the split. If workers in a given job will work for $x, there is no need to pay more. You know this is true as you

One’s willingness to stick around determines the split. If workers in a given job will work for $x, there is no need to pay more. You know this is true as you are watching a situation where workers will no longer work for $x play out. The difficulty in keeping one job filled is not dependent on another job. The difficulty in hiring a janitor does not impact the difficulty of hiring a software developer.