The argument there was that you could scale up an LD and it would look as good as film, which was nonsense. A 35mm print could resolve more detail than the current BD, it is just that the ones printed in 1977 don't, and weren't meant to show that level of detail.

If you used the same neg elements that were used to make the BD, but scanned them at 8K and then printed to 35mm via a laser process, the 35mm would have way more detail than the BD.

The existing prints of Star Wars don't show some of the details that the BD does, it doesn't mean that any 35mm prints cannot resolve greater than 1080 lines.

Plus, as said before, the prints were always designed not to have that detail, it wasn't desired. Had they wanted to, even at the time they could have made a print that held a lot more detail.

But for Star Wars, the point is moot, the prints and the BD are all we have, no one is getting a hold of the negs any time soon. Which is just fine, if you want to see how Star Wars looked in '77, you soon will.