Weird, isn't it?
the 68000 (and even the 6809 before it) could support multi-tasking quite well (even without an MMU), but it took Intel three revisions before they could get it right.
How'd we blow that advantage?
Software.
The reason that you need a 386 to multitask is because everyone wanted to run their old dos software, which assumed it was the only program running.
It would be trivial to write a multitasking operating system for an 8086, however you'd have no software to run on it. There was no reason to ditch all the software and start again, because the 8086 wasn't quick enough to warrant it.
I don't think anyone realised just how big and important the PC would become, or it would have been designed better.
