It is easier to make the justification in a lot of orgs that you need to go out and hire someone to replace someone who left at "market rate", than that you need to pay someone x% more, based on work that is probably nebulous to whoever you need to make the case to.
I don't think there has ever been a time where this has not been the case outside of very small companies or niche operations. The same sort of incentives are endemic in a business of any scale, because ultimately org structures end up as pyramids and people will intrinsically compete to be at the top