It's a crying shame that Dylan did not become the systems language of Apple's new era — it's really quite lovely. Much nicer than Objective C, though undoubtedly trickier to compile efficiently.
Objective-C had the advantage that it worked while Dylan struggled to get an implementation that was acceptable. It would have been interesting if it had made it onto the Newton or got a compiler that could do PowerPC acceptably.
Deterministic realtime attribute was required condition on Apple product, and any GC based language was not acceptable at the time. But sometimes I think they could solve the issue if they could research longer.