From a senate staffer …
Understand that on the Hill, after Rummy, Gates was like a blast of fresh air. People found him candid and responsive (as opposed to arrogant and dismissive). I think most Democratic senators actually like and respect him, and most staff seem comfortable with keeping him on for some defined period.
Maybe that’s a sad reflection of how low Rummy set the bar — that we celebrate mere competence and professionalism — but there you go.