The problem is that the goal is not to make every job do equal damage. The goal is to have some do other things as well.

If I have an ability that provides a group wide mitigation or movement buff or that can give me intense mobility... how much DPS should I lose for that is pretty fuzzy and can often depend on things like player skill. That’s just some of the reasons dancer SPS is low. Does the community value that high mobility more than they would another X points of DPS? What if it’s equal value? How does an automated system know which to favor? What if it’s equal today but tomorrow the community has a preference?
What is the neef is because the community has too much of a preference? As in weaken a job to encourage other jobs to be played...

A major amount of balance is actually balancing not the numbers but the moods and expectations of the players and the design team. Something best left to human hands.