“And we'll never be royals...
It don't run in our blood,
That kind of lux just ain't for us”

Lorde – Royals Lyrics on LyricsMode
EXPLANATION
Although you are not rich, you can be happy or even more happier than others.
EXPLANATION
She is trying to say that she doesn't exactly care about fame and money, she just cares about being happy. She is also stating the reasons why she thinks this.
EXPLANATION
Lords means when it doesn't run in our blood she's saying that she doesn't have royal blood to be a queen or princess.
EXPLANATION
Lorde is saying that she doesn't have Queen Kate isn't exercising in her veins like all other celebrities.