Yes, yes, you are totally correct - delivery can make all the difference.

But I have to add that my main problem is that I am a scientist and big part of my job is to read immense amount of literature and memorize/connect often obscure terms. So when I read for pleasure (I love my job, but still) what I tend to enjoy the most are character heavy, emotional books with beautiful prose, written by people with deep understanding of life. Quite opposite to the academic literature.

So you are right, yes, this slog issue is not restricted to SF (e.g. I don't read epic fantasy either; GoT and LOTR books I skipped myself as well), but SF in particular is something I really want to dig deeper, as there the ideas challenge my brain and remain lingering far after I finish the piece.

But! - I prefer to do it without being forced into a memory challenge. Because if I start and within the first two pages there are 15 names and 3 planets and lots of traveling (i really damn hate descriptions of pure traveling, like please lets just skip that part) then I lose interest in the main idea and the ideas are what I am after.

So Tldr yes, you are absolutely right, it is also the prose and the delivery, but still no prose or delivery would keep me long motivated or make me deeply enjoy reading work which has too many names or weird, invented terms.