In some cases yes. The band I'm best qualified to talk in this regards is Nightwish as they are by far my current favorite and are on their third (and by far best) lead singer. I could give the whole details but it would be long, I started to do so and realized that no one except a Nightwish fan would want to read the novel I had started. Tarja, the first singer, was fired for being a diva who thought she was bigger than the band and being too limited vocally as she could only do operatic. Anette, the second lead singer, was fired for thinking she was bigger than the band when she threw a fit about the band using the backup singers from the opening acts to sing lead on a night when Anette was rushed the hospital just as Nightwish was set to take the stage. Nightwish was faced with a difficult choice that night - cancel and send thousands of fans already in the venue home angry or give the best show they could letting Elize Ryd (current lead singer of Amaranthe and backup singer for Kamelot who opened for Nightwish that night) do what amounted to karaoke as she had to read off a lyrics sheets. They chose the latter and Anette was apoplectic over it. Nightwish's current lead singer, Floor Jansen, is by far the best of the three in talent and attitude. Floor can sing anything from opera to death metal grunts and can shift back and forth with ease and she understands and accepts that Nightwish isn't "her" band that she gets to control and dictate too. She like the rest of the band understands that Nightwish is Tuomas Holopainen, the keyboardist who writes and scores all their music. Its not much different than a group like Nine Inch Nails which is really Trent Reznor and session musicians only unlike Trent, Tuomas doesn't sing.