> ISTM that if Microsoft had managed to add preemptive multitasking to Windows 3.x in a backward-compatible way, this would've given us as close to an Amiga-like OS as one could ever hope to run on 8086 and 286 hardware.

8086 didn't have the instruction set to do preemptive, and the 286's memory model was 64kb pages... and barely good enough. The enabler for MPC (Multimedia PC) was the combination of 386 (and 386sx) + 16 bit sound card + CDROM + PCI VGA+.