I think every band/musician who breaks big is extremely lucky. You can have the talent (but that is not really necessary) and you can put in hard work (that is more important than talent imo), but you have to be at the right place at the right time to be successful, and that is not something you can control. You either have the luck or not.
Just the other day I stumbled on YouTube on a short video when Ronnie James Dio was discussing Ritchie Blackmore, and he said something along the lines of "I owe a lot to Ritchie, because he got me famous. I would have gotten there eventually, because I knew I was good, but it would have taken more time without Rainbow".
Just imagine Blackmore going on with Deep Purple... Dio loses the Rainbow window that places him in the perfect position to step in Black Sabbath at the time he did (Ozzy gets fired AND Blackmore wants to be more commercial prompting Dio to leave... think of the odds), and who knows how it would have gone.
If you think about it, while on one hand we're lucky to have all the bands we have, think of all the bands we didn't have. Ever wondered "Man, I'd really like a band like X but with more Y and maybe a little touch of Z".... well, maybe that band COULD have existed but the most talented guitar player of a generation broke his leg, spent a month in bed and missed an audition with another singer who could have ignited a creative fire.... possibilites are endless!
Kinda like if we want to bring it all on a more philosophical and broader term.... we are so lucky that Leonardo, Newton, Beethoven, Einstein and the likes existed, but we got also Hitler and Stalin. Maybe a musician who could have become better than Mozart died in the cradle. Maybe a medicine student who would have went on to discover the cure to cancer died in a car accident. Ok, I'm derailing too much I guess
But maybe keeping it to music only, it could be a nice idea for another thread, "lucky streak of combinations that made great bands possible" and "kind of bands that if they would have existed in a specific time could have been huge".