Where do you get the "inferior support for multi-threading/multi-core" from? SBCL and ClozureCL (among others) support both with no issues.
Dated tooling? Not if you compare it to Clojure tooling, SLIME is lightyears ahead in terms of robustness. I've lost track of the Clojure REPLs (nrepl, CIDER, inf-clojure, ...) that still suck.
Re: "smaller ecosystem, not as many libraries", surely you are joking or not at all aware of things like the CMU Common Lisp repository. If we disregard Java libraries, Clojure doesn't even come close to CL code that has been made available over the last few _decades_.
One doesn't need CDRs or another (expensive, time consuming) standardization process when there are great portability libraries (FFI, threads, sockets, convenience macros, ..) or one can pick a defacto standard implementation that offers all of the above.