I think PRISM will sell around the same as OOTB. It's definitely not crossing 2 million. I don't think it has that much ammo left. Teenage Dream was practically her Good Girl Gone Bad.
It'll do a little more I reck, perhaps struggling over the 2m line- but only via the strength of huge discounts and continually doing huge promo platforms for little actual benefit.
Even if it did that for like 20 more weeks TD style (that's even assuming her next singles went #1) that'll still be like 400k only bringing it to 1.6M.
PRISM's future performance depends so heavily on the single choices, can't really predict anything. If This Is How We Do, Legendary Lovers, Ghost and Spiritual never become singles...
Blurred Lines vs. All Around the World vs. Pusher Lover Girl
Take It Easy On Me vs. Boyfriend vs. Suit & Tie
Ooo La La vs. As Long As You Love Me vs. Don't Hold the Wall
Ain't No Hat 4 That vs. Catching Feelings vs. Strawberry Bubblegum
Get In My Way vs. Take You vs. Tunnel Vision
Give It 2 U vs. Right Here vs. Spaceship Coupe
Feel Good vs. Fall vs. That Girl
Go Stupid 4 U vs. Thought Of You vs. Let The Groove In
4 The Rest Of My Life vs. Die In Your Arms vs. Mirrors
Top Of The World vs. Beauty and a Beat vs. Blue Ocean Floor
The Good Life vs. One Love vs. Dress On
Pressure vs. Be Alright vs. Body Count
Put Your Lovin' On Me vs. Believe
Robin: 4
Bieber: 7
Timberlake: 2
White King of R&B has been spilled!