Humphries also plays one of the most important positions on the field, second or third depending on if you value pass rushers over blindside blockers; and while in the grand scheme of things, he's not better at LT than Budda is at safety, his value comes with being solid at his position.
It would be considerably harder to replace Humphries as a LT than it would be to replace Budda.
Both are undoubtedly overpaid, however. As
@kerouac9 and I have said, much of the motivation to overpay for our own draft picks could be pinned on Keim wanting to dispel the notion that he's not good at evaluating rookies.