Your memory seems to fool you a bit.
The Commodore Amiga got a 32 bit processor before the PC and might not even be the first consumer computer with this. Preemptive Multitasking too: AmigaOS got it from the start Unix even long before - OS/2 was a huge disaster and not really a successful OS. The PC did have to wait for Windows NT for a somewhat successful OS with preemptive Multitasking. So the PC wasn't really innovative in this points (and alot of others) too.