The Gates quote was "640k ought to be enough for anybody", and it's been wildly misinterpreted by basically everyone.

The IBM PC had already picked the 8088, which had a 20 bit addressing architecture regardless of whether or not 1MB was "enough" or not. The issue Gates was addressing was whether or not DOS's choice of 640 as the barrier for loadable program memory management was enough given that it was only about half the space in the machine. And he wasn't really wrong. The time frame between DOS programs bumping up against 640k and "DOS" programs wanting to use the multiple-megabyte flat spaces available on the 80386 (which couldn't possibly have been architected for in software in 1981) was like three years.

If you want to ding DOS, complain not about the 640k limit but about the complete lack of architecture and discipline in the high 384k. Really no one ever got this space under control, and it was a bucketful of undetectable device I/O hazards and too-clever-by-half hackery well into the 90's.