Well, keep in mind this point as well: At the time, there was much frustration that Apple Cambridge spent so much time on their new development env

Well, keep in mind this point as well: At the time, there was much frustration that Apple Cambridge spent so much time on their new development environment, and not as much as we wanted on making improvements to the Dylan runtime (for example, we hired Ken because we concluded that Cambridge would not get around to threads in time to matter to us). That said, I have nothing but respect for what Apple Cambridge accomplished. Oliver Steele who was involved with the Dylan IDE on the Apple Cambridge team has said that they spent too much time on IDE features, if I recall correctly. Given that, it is pretty likely that they lacked a tree-shaker to reduce executable sizes (https://groups.google.com/forum/#!topic/comp.lang.lisp/pspFr1XByZk https://groups.google.com/forum/#!topic/comp.lang.lisp/pspFr...). It is also pretty unlikely that they'd spent enough time on reducing the memory usage and so on. (It is worth noting that even today, Open Dylan hasn't got a tree shaker.) Bringing up a whole new ecosystem from scratch is hard work!