I mean, the Queen had no problem with releasing an album every year for half a decade, and the GP never became sick of her. Almost all of her songs became hits (not everybody has that), and we all know how many smash singles she has released so far.
Why haven't the GP become sick of Rihanna and her 14 #1 hits? Why did they love her yearly releases so much? I can't imagine someone else releasing every year without receiving a huge amount of backlash.
She played the media game really well for many years, her PR team was top notch. And Rihanna is simply a hitmaker, she picks the right songs and they resonate time and time again.
Because she's likable, authentic and doesn't claim to stand for things she doesn't actually subscribe to (and end up looking like a polarizing hypocrite). The GP does not like fickle artists.