[oscardssmith]

I haven't used lisp a ton, so I might be missing something here, but as I understand it, multiple dispatch in lisp is opt in. The downside of this is that since it has a performance penalty, people didn't use multimethids for core functions like +, so you lose the benefits multiple dispatch offers.

[lispm]

Still a Lisp system may have thousands of Generic Functions with ten thousands of methods. One Lisp implementation I use has that many out of the box. Incl. various I/O related code: streams, networking, graphics, user interface, development environment, ...

Even though low-level numeric code might not be written with them, large parts of applications often are written using them.