They've all had their down moments. Whether it's a single or an album.
Rihanna - Rated R (and countless singles that failed to make an impact) but she has been consistent
Gaga - arguably ARTPOP saw lower album sales (but this was in a year that that albums didn't do so well all around, and people did hold her to high expectations) but single wise she only scored 1 top 10 hit, which is unusual for her.
Katy Perry - was overshined when she debuted by Lady Gaga. Thinking of You, Unconditionally, This Is How We Do, Birthday
Beyonce - 4 (not many of the general public would know this album even existed)
Taylor Swift - numerous singles haven't been huge successes globally
Nicki Minaj - Pink Friday: Roman Reloaded, The Re-Up (i loved freedom) but the album failed to succeed to standards, and overall is very hit and miss (which is probably expected as she makes rap music as well, but many of her pop attempts have failed Va Va Voom, Pills n Potions
Britney Spears - Britney Jean
They're all queens, they're constantly spoken about, and let's face it they've all made some sort of an impact on pop culture, which is why we're here speaking about them, they're all going to have their ups and downs, and if they don't, it probably means they aren't growing very much artistically, or easily jump on the trendy bandwagon.
