Johnson was his college buddy and he got rid of Jimmy because Jerry felt Jimmy disrespected him.
Parcells called it quits when Jerry started forcing players on him and said that Parcells made him feel uncomfortable. Jones also admitted that he only signed Parcells to bring legitimacy back to the franchise so he can get the stadium deal approved.
Switzer was a college wishbone coach with zero NFL experience and had been ran out of college several years earlier. Again, this was someone that Jerry knew personally. He had no business being the head coach of an NFL team.
McCarthy was putrid his last two years in Green Bay. His players hated him. He was late to his own practices. He also lied to get the Cowboys job.