I don't think being known on a first name bases says anything about the artist success/relevance.
It's just that not many other artist share their name. Name another artist named Whitney, Mariah, Celine, Rihanna, Beyonce, Adele. Can you even? It has more to do with their names being rare in the industry than it has to do with their success.
Michael Jackson is the perfect example. You say Michael and people's minds jump around to Jackson, Jordan, Buble, Bolton, etc.
Exactly.
In no way was I trying to suggest that because an artist is only known by their name first it equals relevance.
Katy is not known on a first name basis....perry goes along with it everytime
No one calls her just katy in interviews they always say her last name as well
Some singers who have stage names with two names, such as Avril Lavigne and Britney Spears. I think these two are the perfect example of just going "oh Britney was there" or "oh Avril was there" and you'd know who they were talking about. Mostly though if they're not known just be one name, a second name is needed for their description.
Why are people saying Britney? A lot of people say "Spears" when they interview her.
Yeah but if someone said they were at a Britney concert. You wouldn't be like "who's that?". Where as if you were at a Katy concert, you could go "Katy who?".
While living, Selena Quintanilla Perez was known as Selena. When she started making her English-crossover with the songs "Dreaming of You" and "I Could Fall In Love", she was known as Selena.
I also don't think Kim's full name is widely-known, correct me if I'm wrong booface. <3