Lisp as practiced nowadays is
mostly found in small teams with low turnover. As such, features of the language that necessarily have to scale with larger team sizes and turnover rates are probably just not that important to its current user base.
There's a Go code base that a friend and I first wrote 5 years ago and we incrementally update it as we find small bugs because of a system it interacts with that changes. We usually touch it once every quarter. I've had no trouble re-reading the code base and keeping it up-to-date. I can't say the same for a lot of other code bases I've worked in.
