What do you mean right? You said this is different, I pointed out that it is literally exactly the same. That is not agreement.
The rest of your post is simply factually incorrect. People did not stop doing that, such systems continued to exist through the 90s and 2000s. They still exist right now. They became less common, but that had nothing to do with "the interconnect just wasn't fast enough". It was because intel CPUs became the fastest available, and racks full of small intel based systems were (and are) massively cheaper and entirely sufficient for the vast majority of uses. The speed of interconnect fabric kept up just fine.
The rest of your post is simply factually incorrect. People did not stop doing that, such systems continued to exist through the 90s and 2000s. They still exist right now. They became less common, but that had nothing to do with "the interconnect just wasn't fast enough". It was because intel CPUs became the fastest available, and racks full of small intel based systems were (and are) massively cheaper and entirely sufficient for the vast majority of uses. The speed of interconnect fabric kept up just fine.