Re: Imagine anything as efficient
The OS made the simultaneous I/O possible which is way then went with pre-emptive multitasking to be able to service interrupts. You could talk to everything, all at the same time, and it didn't grind to a halt. On everything else if you did something crazy like read the disc then you probably couldn't talk to the rest of the hardware until you'd finished.
The CPU didn't have MMU but apart from that the implementation was sound (remember the 030 came out as late as 1987, two years after the Amiga's release). I guess nobody complained about lack of memory management on other computers of the time because you couldn't even properly multitask on those.
Then Commodore International were just happy to coast on the initial success. R&D never made it into end products. ECS and AGA were late and AAA never appeared but even around the time of Commodore UK folding (the last part of Commodore to survive), Exec, Intuition, and so on were still practically indistinguishable from magic when compared to Windows 3.1 and Mac's horrid APIs.
I guess Linux is the closest thing there is at the moment to the Amiga's OS, which was UNIX inspired after all (although an earlier, less bloated, UNIX). I suppose BeOS would have been a little closer to the spirit of the Amiga but I never got to play with that.
But still don't know how contemporary OSes have turned into gigabyte-sized things and are hardly more functional while running on CPUs which are orders of magnitude more powerful.