The impression I got just watching as a casual player throughout the duke nukem/keen->wolf3d->doom->quake days and the subsequent breakup of id and interviews C

The impression I got just watching as a casual player throughout the duke nukem/keen->wolf3d->doom->quake days and the subsequent breakup of id and interviews Carmack has given, is that Romero let the early fame and success get to him and lacked the self discipline to keep pulling his weight while Carmack was substantially carrying the company along from his perspective. They had equal shares and were all very young, the only option for them at the time appeared to be parting ways. Carmack has voiced in multiple more recent interviews that in hindsight there were probably better options to make things work out, but they didn't have the maturity and experience at the time to pursue them. Given this context I don't think it's surprising that Romero would crash and burn on his own after being pushed out of id. The self-discipline and maturity side was only more critical to success without the id team's support, not less.