In my estimation commercial success would be like 40% with cultural impact no more than 10%.
I think that's ridiculous. If anything, commercial success should be the least of the four criteria. There are tons of artists that were huge commercial successes and contributed little of real importance to rock music. Artists like Journey, Hootie and the Blowfish, Heart, Pat Boone, the Osmonds, the list goes on and on. None of them are worth one Ramones, Sex Pistols, Velvet Underground, MC5, Gene Vincent, Eddie Cochran, Jerry Lee Lewis, and so on.
My girlfriend Diane was born in 1948. When Holly died she was about to turn 11 years old in a few days. She had no idea who Holly was, but knew who Valens was because "Donna" was a huge hit at the time. Holly was just not that well known in the 50s, as three of his four really big hits up to his death were by the Crickets. Only "Peggy Sue" was a big hit by Buddy Holly. Some other kids told Diane that Holly was the guy who did that song "Peggy Sue" a couple of years ago and she then remembered him, but most people at that time did not even realize that Holly was part of the Crickets. She also realized who the Big Bopper was after being reminded that "Chantilly Lace" was a huge hit just a couple of months before the plane crash, and I think may have even still been on the Billboard top 100 that week at the end of its chart run.
I really don't think Buddy Holly's notoriety should be measured by the experience of some random 11-year-old.
The point is that the name "Buddy Holly" did not mean all that much in the 1950s until he died. He did not release a single in 1958 that made the top ten
"Rave On" hit #5 in the UK in 1958.
and none of his solo singles even made the top 30 after "Peggy Sue" until "It Doesn't Matter Anymore" did so after his death.
Where did "Maybe Baby" chart in the USA, Bruce?