I never said any of these things were impossible. I'm just pointing out that these are hurdles and complications to overcome.
Ones that cost money. Which means a higher budget. Which means it'll be that much harder to convince studios that are typically risk averse to bankroll the thing to begin with,
And no, it's not as simple as "get some real stuff and glue things on it to make it look alien." At least not if you want to do it right and not have it look cheep and nasty.
It takes a team of production designers and concept artist to come up with a coherent aesthetic, from the sets, to the costumes to the props. Then they have to clearly delineate within those parameters so the audience can tell at a glace which of the main groups they're looking at and where they are in the world. Then they have to fabricate all of it for everyone in frame.
Unlike the likes of GoT, Black Sails or the Marvel Netflix shows they can't just rent a bunch of pre-existing costumes or props, (there are literally warehouses full of period costumes, swords, cloaks flintlocks, and vintage cars out there for just this purpose) nor can they use any existing location interiors without significant redressing. Every extra will need an entirely custom costume, not just the main cast. That's *thousands* of units times hundreds of thousands of work hours. It's far from simple.
Again, not impossible, just another layer of complication and cost. A Dune production done on the cheep will look cheep. There are no real corners to cut. The more you have to spend the harder it's going to be to convince the money people it'll return profit and given Dune's track record of less than successful adaptions and next to zero revenue in merchandise sales, that's going to be a *very* hard sell.
So yeah, I wouldn't be at all surprised if this implodes or just drifts into obscurity before the year's end.