Running decades-old code on modern implementations is also a characteristic shared by other languages (e.g. QBasic with FreeBASIC) so I'd hope it's not anyone's main motivation for Lisp. Still, it's a big plus. This is a great writeup to see how to start tackling the elephant that is CL...
Elephant? Bit of a mixed metaphor, almost a malaphor, no? I'd say "tackle the behemoth" or "slay the dragon" instead. Elephants aren't usually tackled, they merely reside in rooms.
