If you are familiar with Led Zeppelin, you'll know that singer Robert Plant and his family were vacationing in Rhodes, Greece in 1975 when they got involved in a horrible accident. From then on, it never really was the same for them, although the big trauma was when his son Karac died in 1977.
Is it possible that Led Zeppelin can keep on going at their current pace if that didn't happen? At 1975, they were at their peak... and nobody sounded like them.
Come to think of it, I'll ask that if Karac didn't die, would they have broken up? I am inclined to say if Bonham still dies.