Low self-esteem/harboring insecurities (be they generalized or specific) is not symptomatic of narcissistic personality disorder; quite the opposite, in fact. The primary diagnostic component of narcissism is a sense of entitlement, which is a catch-all circumscribing most of the other behavioral traits listed.
The true narcissist takes what he wants regardless of any (legitimate) objections from others to the contrary (the fact of his desire is his own self-justification for his actions). For instance, he thinks he is entitled to use your body as an instrument of his own pleasure even after he’s been told “no” repeatedly -- he selfishly casts any contravening interests to the wayside.
The true narcissist will also operate from an implicit premise that he should be able to say/do whatever he want to others with the expectation of having immunity from any repercussions from his words or actions. The narcissist proceeds as if he has a license to be rude/cruel/offensive in his dealings with others and will become angered when he is held accountable.
Hilariously enough, the true narcissist may even be completely oblivious to the fact of his disorder, which may lead him to ascribe these toxic qualities to the very same people they have victimized in a cowardly attempt to cast them in a negative light and make them out to be the bad guy.
Taylor appears to exhibit some of these traits but the foremost example of celeb narcissism is still Madonna. You could argue that there's no way she could have attained so much power if she weren’t a true narcissist, but I am in complete agreement w/ you that Madge (much like other monstrous narcs) will undoubtedly die alone.
the female vocals 
