Not to sound boomer-ish but we truly do live in a time where things that provide instant gratification become increasingly dominant in our daily lives. First example I can think of is the act of scrolling aimlessly through social media to get your daily fix of dopamine which is a habit which has even spread to my grandparents. It's the same with movie-watching. The modern general audience will always be naturally inclined towards things that satisfy their dopamine needs which is why fast-paced films where action and comedy is being delivered every 5 seconds will always be king at the box office. We went from a 3 hour family drama being "The Godfather" to a superhero movie being "Avengers: Endgame" as highest-grossing film of all time. It says a lot.
There's not much you can do to change the way the audiences are nowadays. But you can make some minor changes to the film adaptation to make it appear more accessible and entertaining to them without comprising the integrity of the book which is something that's been done for most film adaptations in the past. Action scenes like the Harkonnen attack will be beefed up. The characters will be beefed up and more humorous and relatable to the audience. Also Dune is an incredibly rich universe with some of the best worldbuilding I've seen and read of, so there'll be plenty of visual spectacles to keep them intrigued, the sandworms being the most iconic one. I'm not too worried about the general audiences' reception to Dune, I believe the biggest obstacle for Dune's box office success is this is this pandemic bullshit and the decline in theaters.