Operating systems that pre-dated MacOS 9 had pre-emptive multitasking. MacOS "moved forward" by adopting one of them (NeXT OS) and building their platform on top of it. I'm really unsure what point you're trying to make here.
I'm trying to say, that at that period of time, MacOS 9 was stuck in the past, even compared to Windows. This was in reference to Emacs limitations as a platform.