This really only makes sense for service-oriented software. Not all uses of clojure attempt to saturate use of available resources, and here STM is a win.
But the OP implicitly assumed everyone was writing "production" software, assumably as part of a commercial service offering.
Although he didn't reiterate it in the STM section, up front he was pretty explicit about what he meant by "production" software, really a specific kind of production software. So the recommendations might not apply if you write a different kind.
To make my biases explicit, I mostly write webapps and data analysis on servers in the cloud. If you use Clojure in significantly different applications, these recommendations might not apply to you.
But the OP implicitly assumed everyone was writing "production" software, assumably as part of a commercial service offering.