I think it's easy to overstate the impact first-movers have on any given industry. The 3D FPS genre was already being explored in the 70s and it's a somewhat obvious direction to explore on the PC as the hardware becoming ubiquitous in American homes matured enough to make it possible.
Carmack is a smart guy but it's not like there wasn't going to be a competitive PC game industry in his absence. Ken Silverman or Tim Sweeney come to mind as alternative first-movers in the space, I don't think it would have been much later.
The games might have been less violent for a bit longer without id though.
> The games might have been less violent for a bit longer without id though.
Probably not. They were just channeling the culture which was a lot of heavy metal and horror/action movies. Personally for me in my early teens it was a nice outlet for feeling powerful in a game rather than bullying some kids at school or whatever.
Releasing the source code for Wolfenstein, Doom, Quake, Quake 2, Quake 3 was very much a Carmack thing. Source code releases for extremely successful, closed, commercial projects remains very uncommon (though it is fair to point out that the current Unreal Engine code is published.)
We'll never know is the real answer. How sooner would the modern lightbulb have been invented without Edison, the affordable automobile without Ford, etc. He put in the work and made it happen before anyone else, and that's damned important IMO.
Carmack is a smart guy but it's not like there wasn't going to be a competitive PC game industry in his absence. Ken Silverman or Tim Sweeney come to mind as alternative first-movers in the space, I don't think it would have been much later.
The games might have been less violent for a bit longer without id though.