Here’s my Dune part one and two summary. Correct me where I might be missing something. Spoilers abound.
The Harkonnens have been mining Spice on Arrakis for decades, and have become richer than e...
Many of your questions are valid but Frank Herbert goes deep on backstory where movie will not be able to. So, a key piece of backstory is missing. Machine computation throughout the whole realm is outlawed. This has a myriad of effects on their society including societal and genetic specialization. Its my favorite book, I hope you'll read it (if you haven't).