Lorde isn't trying to beef with rappers or anything; she's just trying to speak to her peers, i.e. those who might not be able to afford the finer things in life. She's known to frequent thrift shops and was working in an office while at high school just a year ago. Lorde writes music from that perspective.
She explained her reasoning in her feature for Interview magazine. "Around the middle of last year I started listening to a lot of rap, like Nicki Minaj and Drake, as well as pop singers like Lana Del Rey," she said. "They all sing about such opulence, stuff that just didn't relate to me—or anyone that I knew. I began thinking, 'How are we listening to this? It's completely irrelevant.'"
She adds to the sentiment with NPR: "I've always loved hip-hop, but as a fan of hip-hop, I've always had to kind of suspend disbelief because, obviously, I don't have a Bentley," she says with slight snark. "There's a distance between that and the life I have with my friends going to parties and getting public transport and doing the things that every other teenager does."