[Manishearth]

Rust, too, had an optional GC (where the choice is per-data, not global) for a long time and still intended to be a systems language (And was pretty successful at being systemsy IMO). I think there was a time when &-pointers didn't exist and all sharing was done through the GC too. At one point there was a realization that the new borrowing system could be used to write GC-less programs pretty easily, and that was a turning point after which the GC started being phased out in community usage and eventually removed from the language.