I guess the irony is that most of the interview tactics now focus simply on comparing candidate A to candidate B, in contrast to learning about candidate A or learning about candidate B and evaluating their suitability based on their skills and experience.

If you ask both candidates a question like "Johnny climbed up to the top of the hill, where was Johnny when he stopped climbing?" and then get a blank stare from both candidates then you are going to conclude that you can't find any 'qualified' candidates because they can't answer a dead-simple question.

The vetting of candidates used to be contributions to software product releases and publications (in addition to degrees and GPA). A motivated hiring manager could also search mail archives of popular open-source projects.