The milieu of Frank Herbert
novels is one that is wonderful to read about, but is not a pleasant one for an average citizen. The common citizenry are basically owned by their noble house
in a feudal system
. If they are lucky, they live under the good House Atreides
or the like who treat them fairly. But if they are unlucky, they live under the House Harkonnen
or the like, and are hunted for sport.
Either way, they have no recourse to a higher authority, and are in danger of becoming collateral damage in the status battles between noble houses.
The Butlerian Jihad abolished many devices, and thus created a need for Spacing Guild navigators, mentats and other specialisations.
The bitter irony of the Butlerian Jihad is that whist it succeeded in ensuring that no human was enslaved to machines, it reinstated the desire for human slaves. Whilst it ensured that no mechanical tool would be the equal of a human, it made many humans into special-purpose tools to serve their human overlords, and the rest into serfs.