I pretty much agree with this assessment of why any movie adaptation of Dune seems destined to fail:
Dune is presented as a subversion of the hero's journey and of the adventure quest. By the end of the novel, Paul's prescience means that everyone has effectively become a clockwork mouse on rails without free will and, even with the jihad, humanity is doomed to inevitable extinction. I doubt the average punter wants to spend several hours in a movie theatre assimilating that message.
In a 1969 interview, Frank Herbert described the action denoument of the novel as deliberately "high camp". The 1984 movie got that aspect correct.
It took Frank Herbert three further books to unbind humanity. Adapting those would likely require at least two further movies.
A TV miniseries would be the way to go but it would likely lose a lot of its audience before it could get as far as God Emperor of Dune.
I just hope a movie adaptation of Dune can tackle and subvert the current zeitgeist of people looking to supermen (Putin, Trump, etc.) to save them.