The song is not doing well because it's really not that good. It is not exciting, it kind of does not go anywhere. The video is cute.
And the Britney stans will not blame Iggy for the current position the song is in when before the single even came out they kept the "feat. Iggy Azalea" on their single covers, changed it in their iTunes and then said Iggy was barely on the song anyways. It IS on Britney's album, too.
The song could still pick up, but who knows.
