That derisive tone about it being a retention issue prove otherwise. Grow up and realize you have a bias in this issue, otherwise you wouldn't be so talkative on the subject.
But, playing along--how about divorced dudes who now get dependent rates for their kids (who mostly don't live with them)?
Technically they're single and "worth more" to the service...but get money of those "of less worth."
You have no idea what they'd offer unless you were involved in the hiring process, or someone spoke out of turn. Person might negotiate for less not knowing what they could demand == more value for company. Or, perhaps they have a particular skill/experience and could negotiate for more.
And you had no say in those moves? The company thrust it upon you as a requirement you were indentured to fulfill? Thank you for your sacrifice.