didn't I put "average" in the comment already? (and to be fair, this is the group the post was talking about when making the calculation). I know and have helped some brilliant engs at google reach l5 with much shorter time frame, but it's not the norm.
given you seem to be from google, there are various stats w.r.t promotion timeline that offers more insights about the average case internally
given you seem to be from google, there are various stats w.r.t promotion timeline that offers more insights about the average case internally