I think that 2M WW is reachable without a big smash. Any single that would be as popular as DWUW (with a video this time) could push the album up to 2M. I think 1.8M WW is something more realistic, though, if there'll be no more promo.
At least, ARTPOP is still high on Amazon
http://www.amazon.com/best-sellers-m...pd_dp_ts_m_1#2
#22 (25) ARTPOP, Lady Gaga
EDIT
#21 (23)
It's #6 on Amazon China as well.
Doing REALLY great on Oricon daily:
#11 (21) ARTPOP, Lady Gaga