It really is. It took years after the Amiga for the average PC to have preemptive multitasking. The same story repeats with 64-bit machines and multi-processors. In the latter case, it took so long for the average PC to have more than one CPU/thread most current software (and programming languages) simply isn't designed for it and cannot take advantage of those extra compute engines. Even if it were, most programmers never learned how to write software this way.
The PC standard set us back at least a decade, most probably two.
"It took years after the Amiga for the average PC to have preemptive multitasking. "
Partly thanks to the MS OS/2 2.0 fiasco, also resulting it taking ten years after Intel released the 80386 before 32-bit programming became popular. Needless to say, the x64 transition went much better.
It did, but how long after the arrival of the first 64 bit CPUs did that happen? I ran Windows on an Alpha that wasn't much more expensive than a high end Pentium PC while being unbelievably faster. Would it have survived in a world where being able to run MS-DOS isn't so important? I'd say yes. 32 bit programs were the norm with Amigas ans Atari STs from day one. It was only the PC world that lagged years behind every competing platform and that dragged us back when it finally eradicated its technically superior competition.
Most of the kludginess in every modern x86 computer is dictated by the need to emulate parts of an IBM 5150.
I'd also prefer a clean break, something clean like ARM (although it's getting dirtier).
But the Itanium that intel moved on to? That isn't a clean break. It's a mistake. I'm so happy that AMD was able to force them to make something useful instead.
Being multithreaded is hardly important at all. You can just have single-threaded programs, and they'll work. Almost all software doesn't need to take advantage of extra compute engines. Reasonably designed software that could take advantage of multi-threading can be modified to do so, and poorly designed software cannot -- it doesn't really have that much with being written on single-threaded machines as it does with being poorly designed. You can always spawn a worker process if your current process is some hair-brained monstrosity.
The PC standard set us back at least a decade, most probably two.