Romero is a strange figure. Why wasn't he able to really make it after id? From Daikatana to Empire of Sin, everything was a flop, more or less. Who is John Romero?
In some ways Romero actually saved ID software and made everyone a ton of money by working out licensing deals for their game engines. Carmack wouldn't be able to continue to work on his tech and hire Abrash (who optimized Carmack's code) without the money coming out of these deals so he unfairly complained that Romero wasn't pulling his weight for the current project and treated him like crap until he got fed up and left.