Why's there so few main pop girls w/6 million+ digital selling singles? And why's there more boys, and groups that achieved this feat?

Main pop girls with 6 million selling singles according to Billboard:

Adele
Lady Gaga
Ke$ha
Christina Aguilera
Katy Perry
Rihanna

Why aren't the likes of Beyonce, Britney Spears, Pink, Miley Cyrus, Kelly Clarkson, etc, etc, etc doing it like the girls' listed?

I'm pretty sure Girlfriend by Avril sold like 7 million... Or maybe that's worlwide?

Girlfriend sold around 4M in US.

That's WW

Broadway Icon Carly's CMM sold 17 million worldwide, the main pop girls could never

Ke$ha, ha power!!

I don't even count Christina or Rihanna in that group.

I see you, gorl.

Because Britney, Beyonce and P!nk aren't as relevant in the digital era as Christina Aguilera

They all peaked before the digital era.

__________

As for Adele, Ke$ha, Rihanna, Gaga, Katy, and Legend X, their songs are huge and have lasting impact, which helped them sell not for a few months (like most quick little singles do), but for YEARS

Idk, their appeal may not transcend past the female market as well. Men are more likely to buy the songs like Right Round, which impacts sales. They buy those songs in addition to women, but it doesn't seem to happen the other way around (I.e.) a man buying a Katy song

Thank you!

What christina song sold 6 mil? and its an accomplishment but its not the only form of success and one 6m seller doesn't make you a legend

The second group of girls have had "big" hits but they haven't had BIG hits like the one the girls in the first group had.

If they're considering Moves Like Jagger and Hate The Way You Lie, it doesn' count for me. They were merely featured artists.

The list is based on facts, not what YOU think SHOULD count.

Moves Like Jagger

How many of those pop girls are featured artists?

And people say Ke$ha is one of the lesser pop girls...

I think that selling that much is hard because a song has to have wide appeal across all regions. Although digital sales are decreasing due to the popularity of streaming services, I think iTunes worldwide has a lot of potential from emerging countries in Asia and Latin America (like Brazil, India, Russia, Turkey, Mexico, Chile, and Argentina).

I think Miley can eventually get one single up there. Kelly is very popular but I feel like she's more famous in the US. Pink does great pop singles but I guess the longevity factor affects her. We have yet to see Demi Lovato or Selena Gomez get a number one single, though their influence is growing.

But the future can't be predicted and time will tell whether another pop girl will find a spot there (without being called a one hit wonder)

Moves Like Jagger.