From my Quora reading, which prompted a “what, really?”, followed by a smile.

“Is Dune just a cheap ripoff of Star Wars?
No, Dune is a very expensive ripoff of Star Wars.

The actual ripoff was cheap. Frank Herbert watched Star Wars on opening night in 1977, then cribbed a bunch of notes, changed the name of the planet Tatooine to Arrakis, changed the name of Luke Skywalker to Paul Atreides, and pretty much left everything else the same.

The expensive part was building a time machine so that he could go back in time and publish Dune in 1965, twelve years before Star Wars came out.”