Then everyone got video cards and CPU performance stopped improving almost overnight. Sure, we got 200 MHz Pentium IIs, and then Intel jumped warp speed into 1 GHz and then 2GHz and then 3 GHz... but single threaded performance wasn't any faster, and even today is only maybe 3 times faster than it was then, per clock cycle. What really happened is that all of the chip area went to branch prediction and caching.
When chips went from a few million transistors to a billion, I started asking why we couldn't just put dozens or hundreds of the old CPU cores on the new chips. As we all saw though, nobody listened or cared about that. So today we have behemoth chips that still choke when the web browser has a lot of tabs open.
Chips today have maybe 8 or 16 cores, and that's great. But it's 2 orders of magnitude less than the transistor budget could support. Apple's M1 is loosely trying to do what I'm asking. But it's making the mistake of having all of these proprietary/dedicated cores for SIMD stuff. I would scrap all of that, and go with a 2D array of general-purpose cores, each with their own local memories, communicating using web metaphors like content-addressable memory.
In fairness, I think the reason that real multicore CPUs never caught on, is that we didn't have the languages to utilize them. But today we have Matlab and various Lisps and higher order methods that auto-parallelize loops by treating them as transformations on arrays. All of our languages should have been auto-parallelized by now anyway. And not with SIMD optimization magic, I mean by statically analyzing code and converting it all first into higher order methods, then optimizing that intermediate code (I-code) so that the block copies are spread over multiple cores and memories. I can't remember the term for this, it's basically divide and conquer though, for example if fork/join scope was limited to a single function by the runtime. Scatter gather and map reduce are other terms for this.
So right now we have to deal with promises and async and other patterns (I consider patterns an anti-pattern) when we could just be using an ordinary language like Javascript or C, auto-parallelized to run on 256+ cores with something like terabytes per second of bandwidth, running many thousands of times faster than computers today, for far less effort because it appears as a single thread of execution. Then OpenCL or OpenGL or anything else could run like any other library above that, for people that prefer a higher-level interface.
