[jwr]

In a lage codebase, the cost of switching is huge, and if older libraries work well, there is often no clear incentive to do so.

Clojure in general being very stable and backwards-compatible makes it even more easier to just continue using older libraries. So what if the library is "dated"? If it works well, why not continue using it?

(I speak from my own experience)

[coltnz]

Totally agree, I didn't say they shouldn't continue using them.