BEYONCÉ has sold over 3.6 million in 4 months. And the era isn't over. Rihanna's album sold over 3 million in 1 year. Lets do the math.
I think you just emphasized what the OP meant. She sold 3.6M in 4 months, and now struggling because it proved that the sales were heavily frontloaded to begin with.
Does it really matter? Bey has sold that much in how many months compared to how long those other albums have been out? She's dropping, but she doesn't have a hit to keep momentum up