That's indeed one of the 5-6 main themes of the novel as defined by Herbert himself. By that he meant the main ideas he had decided to explore. Rather than writing essays, Herbert used fiction. Most of his novels are speculative fiction in the purest sensse.

Some others "themes" I remember:

- How the scarcity of a vital resource tend to make it the pivot of economy and politics and defined the limit of the possible. It was a topic of exploration inspired by the oil crisis which was already predicted at the time.

- A deconstructiom of the myth of the Hero, worshipped by humans since the beginning of times, in myth and religions and history. Herbert believed that Heroes, especially the Superhero kind, were disastrous for humanity. In Dune, he meant to project this idea on a galactic scale and put the survival of all humanity itself into the balance.

- How the cult of the superhero too often lead to theocracy, and how mixing up religion and politics constantly lead to fanatism and disaster. Herbert thought theocracy the worst kind of government.

There were a few more, I'd need to look. IIRC, Herbert spoke of that in the foreword to one of the novels in the French edition (his forewords/afterwords, or those of his French publisher aren't in the American editions).

Of course there's minor themes and ideas by the dozen, as in all of Herbert's books.

Among other things, Dune has also fascinated economists in Europe in the 70s.