This isn’t a “go back in time and assassinate” someone question. It’s just their musical career never takes off and thus any music they ever would have made is no longer in this timeline.
Similar story, when I was 12 I was late for the school bus and ran about 2 blocks with a full backpack and a snare drum. Ended up puking in the bus aisle about halfway through the hour long ride. Basically the same thing.
If you could go back in time and stop any one person or group's musical career, who or what would it be?
This isn’t a “go back in time and assassinate” someone question. It’s just their musical career never takes off and thus any music they ever would have made is no longer in this timeline.