Of course with the spice and mentats, they could probably use some limited form of prescience to explore possible avenues the future was likely to take. It is a universe in which magic, by another name, works.
Writers that take your approach - it’s all made up so I’ll just make up new rules whenever so feel like it - are rarely satisfying because the reader can’t trust anything or reason about the setting or the characters choices.
This is the problem with J.J. Abrams approach Star Trek and Star Wars. He seemed to take a special glee in arbitrarily violating established conventions in the settings with respect to things like how Warp Drive and Transporter technology work in Star Trek.