What not prog band would've made the best prog?

They'd have to know what it is first, wouldn't they? 

I've got to see this to believe it.  And then probably have a heart attack or something. 

you are? how? 

I almost pulled you up on it after your first retort, but decided to leave it. But you’ve now questioned the idea of these two pop stars three times. If the joke was ever funny, it’s wearing a bit thin.

Julia Marcell, who has not really released anything I would call prog previously, released a quite beautiful prog pop album last year. Gaga and Lorde could easily do the same. And I definitely believe all three would be more than capable of putting out a full on prog album.

The Opium Cartel’s album from last year, Valor, definitely reminded me of Lorde’s music at time. I said as much to Jacob Holm-Lupo, and he said that he and his daughter (who sings on one track on the album) are both big fans of Lorde, so he took that as a compliment.

I'll echo Bowie, Queen, Prince, The Who and the like

I will also say I agree artists like Lorde and Lady Gaga would probably make some valuable prog or prog-esque music if they decided to try

Hearing their debut album "Fresh fruits for rotting vegetables" I hear nothing of the proverbial three chords punk attitude. There are moments (quite many) when they operate on King Crimson level of musicianship.

There were a plethora of British pop bands of that era who had the prog influence - as well as Duran let's consider Japan, Tears For Fears, OMD, Thomas Dolby. Indie poppers The Icicle Works were probably the proggiest of the lot, discounting leftfield weirdoes like Stump and Durutti Column who had a variety of non-mainstream influences and tick the boxes for musically adventurous and experimental rather than overtly proglike. And of course The Fall were basically a krautrock band from Prestwich.