If Kirk would've left the Aints game then sat for the next 2-3 weeks, 1 of 2 things would've happened.
1. Penix shows he's not ready yet, and Kirk is put back in when he's healthy
2. Penix takes the job, Kirk never sees the field again, and he goes into the offseason the hottest commodity in the league after throwing for around 1,500 yards and 13 TDs in his last 5 full games.
Either one of these paths leads to him being a starting QB in the league right now. Instead, his selfish ass sitting on the bench