Notch, Carmack, Spolsky may have engineering in their skillsets, but they are also product (game) designers and executives (and world class ones at that). I don’t think that’s really what people want when they’re looking to hire an engineer for their startup.

As for Bill Atkinson… looking at his Wikipedia page, looks like he was indeed a top notch engineer in the 80s, but doesn’t seem like he worked on anything noteworthy after that? Definitely not in the same league as the other 3 IMO.