None of them came close to the success of Quake, Doom or Commander Keen.

If you examine the list it includes games like "Gunman Taco Truck" by his 12yo sun, SIGIL I/II (Doom mods) and a remake of Dangerous Dave. Most of the money he made post-id came from Facebook farming games.

I'm not saying he's doing nothing. He's extremely talented and achieved more than most of us could ever dream of. I'm just pointing out that after he departed from id neither id nor him managed to replicate the earlier success. Who knows, maybe times had changed and it would be the same even if he stayed.

Their success with Doom and Quake was a confluence of things that cannot be replicated today. Carmack's programming talent gave them at least a year head start versus the competition. They introduced a new genre with no competition. Romero wrote game development tools that made them productive and able to deliver quickly. The artists and game designers created something innovative and fun to play, that stood the test of time.

Duke Nukem was released in 1996, then Unreal was released in 1998 and that's when they lost their technical advantage. The market became saturated with FPS.

Romero and Tom Hall founded Ion Storm which produced one successful game - Deus Ex. He gave up on AAA and went back to creating small games.

Carmack's licensed code was the basis of many successful games beyond the 90s, including Half Life 1 and 2 and the latest Doom games. We wouldn't have Half Life without id Software. Maybe Valve Software wouldn't exist.