Ozzy Osbourne was kicked out of Black Sabbath in 1979 primarily due to his increasing problems with alcohol and drug abuse, which made him unreliable and hindered the band's ability to work effectively in the studio. The other band members, Tony Iommi, Geezer Butler, and Bill Ward, decided that it was either going to be the end of the band or they would have to continue without Ozzy. His excessive substance use, erratic behavior, and frequent absences from studio sessions led to mounting tension and conflict within the band, culminating in his dismissal. The decision was a band consensus, not just Iommi's, and was also motivated by the need to keep Black Sabbath going with a functional singer. Ozzy himself felt he was being pushed out unfairly, although he acknowledged his struggles. After Ozzy's firing, the band replaced him with Ronnie James Dio to move forward musically.
