Jodorowsky's Dune artbook

No, the content has largely not become publicly available in its entirety.

In an interview, Jodorowsky discussed the number of books created:

The Dissolve: You and Seydoux created a massive book that you gave to the studios, showing storyboards and special-effects designs. None of them came back and said, “We don’t want to do this picture with you, but we’re impressed and want to do something else with you”?

Jodorowsky: No. We made 20 books, and every one we made—they went to MGM, Universal, etc.—the answer at every one of them was, “Jodorowsky’s crazy.” Nobody back then would consider doing a 12-hour picture. No one thought about the trilogy until Star Wars came around. In that moment, it was impossible to make a space opera. It was only $7,000 for the rights to the book, it’s nothing, but still nobody wanted to do it.

There are unsubstantiated rumours that only two copies of this "book" still exist, one of which belongs to Jodorowsky. However, he doesn't appear to have discussed this in interviews.

There was some excitement a while back at a typewritten movie script with illustrations that claimed to be "DUNE, screenplay by Alejandro Jorodowsky, adapted from ‘Dune’ by Frank Herbert." However, Jorodowsky derided it as a fake.

The most recent information I've seen on the issue is from an AMA on Reddit with Frank Pavich, the director of the documentary.

He was asked if the book would be published, and responded:

There's been talk, yes. I've heard rumblings that Taschen was interested.

I'm not sure where it currently lies. Is it even possible? Can they even get the underlying rights to the novel again? I assume they would need that, at least. Maybe they're waiting for the documentary to spread a little more and go from there?

If it's even published, I'll be first in line at the bookstore, for sure!!

So currently, the content has not become available but hopefully it will become available in the future.

Not officially, but some suspiciously unique content is available here.