It has nothing to do with Miley. People are probably getting tired of Rihanna. Her next era should be interesting. She better adopt a new personality, 'cause the bad girl thing is kinda played out and I'm sensing a lot of people know it's not the real her.
I wouldn't say Rihanna is fading. If Pour It Up video is being used as a receipt, you have to keep in mind that the video is 4794 months late, it came WAY after PIU peaked inside the top 20 and everyone had already moved on.
In my opinion, it would be more accurate to say Gaga is fading because of Miley. Clearly there's room for only one extravagant/controversial popstar; and Gaga's gimmicks are becoming boring so...
she isn't fading, she is on tour and hasn't released new music.
If she had a new single out tomorrow, it would storm the charts WW and would make year ends lists as per usual
I can't even take this thread serious. rihanna has sold about 20 million more albums than miley, has 6 grammys, 12 number ones, most liked on facebook and most viewed and subscribed vevo artist. If anything its clear that miley is very inspired by rihanna.