I'm so proud of her and the fact that the song managed to stay on top for a couple of days, I don't really care for the actual chart position at this point.
We should not worry about how her singles perform, even lead singles.
She did what she could to give it a push, She gave two interviews, tweeted the iTunes and Spotify link, told us the album release-date.
Her songs don't get much airplay or they don't get any at all. Other acts from Interscope get pushed way harder by the label, the singles are discounted for a long time, endless promo is lined up etc.
Her internet-savvy fanbase who actually buys singles, bought it. The rest will end up buying the album.
Lana ain't pushing her singles on TV or radio, so therefor the songs can not gain in performance. It's just how she wants it. Everything is pretty low-key.