I sometimes wonder what could've happened if he stuck to the 3d graphics space. He once was a great innovator, wolfenstein, doom then quake, he did some innovation in Rage / id Tech 5 with infinite texture streaming but it was full of technical issues. Ultimately around doom 3 / rage, it felt like id software wasn't anything special anymore, they were brought out and then he left Id.
Now the last major innovation in the space came from epic games / unreal engine.
He did his best work when he wrote the entire engine alone. That's no longer possible. You can however plausibly invent AGI alone. He said that an AGI implementation is likely simple (meaning not complex), and I agree. The difficulty is in the method not lines of code, so it's work that fits him.
Now the last major innovation in the space came from epic games / unreal engine.