It feels like that's what @Micah Sweet was asking for ?Again, it's not a binary option. They can aim products at newer players while also providing options aimed at experienced players.
Also just because you're an experienced player doesn't mean you're experienced with 100% of the ruleset equally nor does it mean that some aspects of the ruleset won't become less used and therefor less 'second nature'.
Plus I know that sometimes rereading books on subjects I'm familiar with can sometimes lead to new inspiration or revelations on missing knowledge for me. While I know this is a personal anecdote I know others like that and I'm sure there are many I don't know.

WotC - WotC needs an Elon Musk
I think a book on worldbuilding that was newbie-friendly would be of immense value, and I'd probably buy it and use it even though I've done a lot of worldbuilding, because part of being a veteran in a field that's almost entirely self-taught is realizing that you probably missed a lot of really...

Azzy kind of sounded in reply that since old editions has such things old players didn't need anything more.
And then Micah made the comment you are replying to