Pay gaps for the same position in the same business shouldn't exist and raisea should be for personal reasons
My dream is to be a Veterinary assistant so let's use that as and example. Two or more Vet assistants at the same practice should be paid the same amount no matter their experience or seniority.
And because I don't think there should be pay gaps if someone wants or needs a pay raise it should only be based on their personal circumstances like if they have a baby on the way or they have an apartment or house to pay for. If someone does think they should get paid more for the job responsibilities then all other employees in that same position should get the raise too since they should have the same responsibilities.
(I guess that there are times where one person could have more responsibilities than the other(s) so maybe they would be entitled to a raise without the others getting one too)