"Recently revealed" is more like a confirmation of what I had read many years before; and furthermore, that Intel's 64-bit x86 would've been more backwards-compatible and better-fitting than AMD64, which looks extremely inelegant in contrast, with several stupid missteps like https://www.pagetable.com/?p=1216 (the comment near the bottom is very interesting.)

If you look at the 286's 16-bit protected mode and then the 386's 32-bit extensions, they fit neatly into the "gaps" in the former; there are some similar gaps in the latter, which look like they had a future extension in mind. Perhaps that consideration was already there in the 80s when the 386 was being designed, but as usual, management got in the way.