>> "... artists lose their ability to make art when their brain is infected by money and power."
I disagree. It's largely age based. Especially for filmmakers as novelty is part of the appeal of movies. As the artist ages, I think Yeats said it best: "What can I but enumerate old themes".
Coppola is 85. How many octogenarians are still creatively significant? Yes, they can still put out an album or a film or a book, but their best days are behind them.
Coppola paid for "Megalopolis" out of his own pocket. He wrote and directed the story and cast the actors that he wanted. What is art in its purist form but the self-expression on an individual?
Previously, Coppola mortgaged his home and went legendarily overtime and overbudget for "Apocalypse Now". That's regarded as a classic and was lauded in its time. "Megalopolis", not so much, though time could add a new perspective, as sometimes art becomes more favorably viewed upon reflection.