I believe with the right promo she could be just as successful as them. I would like to see her surpass Miley just to shut up the stans. Like others have said, the times have changed charts and rules are different.
What I do know for sure is that anything she releases will sound much better than We Cant Stop, Hilary would never stoop that low. Other than Miley Hilary actually has class.
Also Jared obviously knows something about her music that we don't, so she's coming