The most important software missing from the new Encore UNIX (Umax) was MM- the TOPS-20 integrated mail and bulletin board program. A friend of mine wrote "bboard" a campus messaging system as a replacement (this was soon replaced with USENET). It had a bad integrated editor, so I wrote my own editor as its replacement, this became the editor JOE. Even so, Emacs was always there as the counter-example. In those days, Emacs was large and slow and had a limited file size, and it was easy to do better if you weren't focused on extensibility.
I don't remember "not running", but I certainly do remember those annoying "garbage collecting... done." messages in C Emacs. The eventual solution from the mid 90s was kind of awesome: improve the garbage collector? No: Just stop showing the message.
I remember getting a DOS port of Gosling Emacs on floppy disk at a computer show (there was always somebody selling "shareware" at those). I lost that disk, and for a long time had no access to the Gosmacs source code, but eventually someone sent it to me. Sadly, we can not share it- James Gosling closed it. Some other Emacsen: MicroEmacs, Epsilon, JOVE and JED.
Is JOE still your own daily driver, or do you use something else now?