Consider that we have parallel stupid small cores, and have had them for years: Most harddrives have full CPU's on the controllers these days, and there are full CPU cores all over the place outside of our "view". E.g. consider things like the Transcend Wifi SD cards with ARM SoC's on board. Many hard drive controllers have full CPUs. You find embedded CPUs "hidden" in all kinds of PC hardware these days.

The PC architecture started out being hampered by the CPU + dumb peripherals architecture, but this was a big departure from the norm during that era. In the "home" market, most machines either had CPUs too weak to drive the peripherals (my first "parallel stupid small cores" system was a Commodore 64 + a 1541 disk drive - you could, and people did, and wrote book about, download your own code to the 1541 and do computations on it) or explicitly used CPUs or co-processors all over the place to offload things, like the Amiga.

My A2000 had of course the 68000 (and later a 68020 accelerator), but also had a 6502 compatible core running the keyboard, a Z80 on the SCSI controller card, on top of the Amiga's custom chips which had the copper, blitter and sound chips that all had limited programmability. The irony is that it perhaps made a lot of us overly gung ho on the 680x0 line (though it does have a beautiful instruction set) because our machines felt so much faster than comparably clocked PCs - hence many of use were ok with not upgrading CPU models and clock rates as fast as in the PC world.

It was first when PC's started sprouting co-processors (graphics cards and sound cards with advanced capabilities first), that the Amiga truly lost its edge (at the same time Motorola failed to deliver fast enough versions of their newest 680x0 models, faster CPU's would have been insufficient) - until then the co-processors and philosophy offloading everything possible had compensated for the by then anaemic average CPU speeds.

Though the 3rd party expansions gave one more fascinating multi-processing step: Systems that would let you run 680x0 and PPC code on the same machine (PPC cpu on the expansion card, 680x0 on the motherboard).

PCs have been steadily sprouting more small cores. They're just not as visible.

On the server side it is extreme: I have single CPU servers at work where the main CPU may have 6-8 x86 cores, but where there may be 30+ ARM or MIPS cores when you tally up the harddrives (dual or tri-core in many cases), RAID controllers, IPMI cards, some networking hardware etc.. But these cores are getting so cheap and so small that we should expect to continue to see offloading of more functionality.

On the Amiga, this was what was our day to day reality. SCSI was always favoured, for example, because it was lighter on the CPU than IDE was (hence universal disdain for the guy that forced engineering to put IDE in the last Amiga models - the A4000 and 1200 - which helped cripple them at a time when they were lagging in overall CPU performance; the man in charge at Commodore the time was the guy that had been responsible for the PCjr disaster..), because it offloaded more logic (and hence was more expensive, hence the cut).

Rather than be exposed to the parallelism, expect that we'll see more higher level functionality being subsumed into peripherals so that the main CPU gets to focus on running your code. E.g. there are TCP offload functionality on some high end network cards.

Just like in the architectures born in the 60's and 70's out of necessity because of wimpy CPUs...

The "one CPU to rule them all" PC is an aberration, born out of a time when CPUs where getting to a performance level where it was possible, and where the norm of single-tasking OSs for personal computers meant it for a short few years seemingly made little difference if the main CPU spent all its time serving disk interrupts while loading stuff.

The norm in computing have been multiple parallel cores. Even multiple parallel CPUs. Often on multiple buses.

And over the last few years we've gone full circle.