The Firefox ESR page makes it quite clear that the ESR is not intended for 'personal' usage (only for organizations). I also couldn't find any links to the download from the main ESR page (there ARE two forms to sign up for the mailing list, though!).
I'd imagine most people also haven't heard of the ESR, anyways, since it's fairly new, and is a reversal of Firefox's long history of quickly abandoning releases.
As for distribution packages? Not an option for Windows/Mac users. Distros often lag behind upstream's major versions as well.