Why did lady gaga quit her tour?

Answer 1

If you're referring to the Born This Way Ball, she didn't "quit" it, she had to cancel it because of hip surgery. Throughout the tour, she was going through chronic hip pain which soon make her unable to walk. The doctors said there was a labral tear in her hip, and needed surgery. She wanted to postpone the rest of the tour, but the recovery period was too long. so she needed to cancel it.

Answer 2

Has nothing to do with her voice. She was sexually assaulted and left pregnant at 19. Do the math.

Answer 3

she didn't quit, the dropped her as they didn't think she had potential

Answer 4

They claimed she wasn't talented enough and she wasn't what they were looking for, but have since asked her to come back to them and she denied.