I think you're all analyzing this all wrong. I think she simlpy means that the sound of the record is what is going to be refereed to as retro in the future. Like with Ultraviolence she was using the term Future Jazz. It's what Jazz music sounds like in the modern day (and will be known simply as Jazz in the future).
She has the futuristic skyscrapers with the old school Hollywood set lights - I can see what she means by future retro as well. I'm super excited for this album. I went to her show at Hollywood Bowl on Monday & it was by far one of the best live shows I've ever been to.