Rihanna is at the point of overexposure with her endless string of singles release. Cheers, a song with "hit" written all over it, starting to stall on radio is an obvious indication to her oversaturating radio. I mean she never stopped since Pon De Replay, even during the aftermath of "08 incident and in anticipation of Rated R, we still got Run This Town to fill in the gap.
One of the reasons I believe contributing to her longevity on radio is because she dishes different sounds and genres with her range of singles released. There's little left sounds for her to do. Although no promo could be a reason, but at Rihanna current standard (Billboard's Female Radio Artist of The Year), Cheers shouldn't be stalling so early. It's a sign.
From my amateurish observation, radio stations are starting to ditch the whole dance and electropop genres and this can be seen with the rise of songs like Pumped Up Kicks, RITD, You & I and SLY. While Cheers seems to fit in the same category, something is still off. We are not, but people out there are probably getting tired of seeing her everywhere. If anything, she should release an EP and take a break and not a new LP which needs considerable promo.
At an extent, she's revolutionizing the music industry by embracing the trend of releasing materials non-stop, probably to compensate for the significant decline of album sales. However, the only noticeable aspect that changes with each era is probably her wig, instead of her vocal and performance skills. I'm not gonna lie, I'm not as excited as I used to when Rihanna is performing somewhere, it's always the same thing. I'm bored.
She's probably enjoying the attention, and the success falling in her lap at the moment. But sometimes, it's best to stop (for a while) when you're ahead.