Don't forget that John Carmack is arguably a programming genius, 3-4 standard deviations above average. Most of us can't maintain the same amount/depth of mental maps as he can, so we need tools to help us
On top of that, Carmack was essentially the singular engineer on his projects. Most others were concerned with making levels, assets, music, etc.
There were others (sorry Abrash and Cash) in the codebase but it was largely John. Which means his bus factor was insanely high. He was the definition of a silo of knowledge. He also used this to his advantage, knowing the company could not replace him.
Most projects of a certain size cannot and do not want that dynamic. It is not a healthy dynamic once there’s some number of people working in close proximity.
I'd say most of us do not have this kind of focus. He actually has two focuses: strategic focus and tactical focus. Strategic focus means that he devotes a good part of his life into building a virtual world and concentrates on rendering algorithms. Tactical focus means that he can work 10+ hours daily for every day for a large part of his life.
Most of us would be lucky to get a quarter of those two focuses.
It's easy for him since he wrote most of the code himself so he knows how it all works and fits together so short notes are all it takes to get the clue, but good luck finding your way around projects where you didn't write 90% of the code and it's constantly changing under your nose from other people's commits.
I currently work every day on a codebase that is >95% not mine and changing, and its very fun. Some days I'm just as productive as on my own projects, sometimes 1% of that.
I think there is great value in letting yourself enter this hacker flow state on other people's code - its new and exciting.
Glad to see this, I'm a mega John fanboy as they come but the reality is this is close to the ideal working env for a hacker of his talents. The single biggest hurdle to good code is somebody else touching it and the other major hurdle is not owning the company/product direction.
Again, I am happy to recognize him as a genius no doubt, but I couldn't imagine he would've lasted in a CRUD Java gulag. Those places... break people.
