Yeah, I totally agree. OTOH I was kind of told the remit of this thread was talking ABOUT Skilled Play, and my commentary on its shortcomings were kind of attached to a frowny face. So, I'm not going to talk about "we can do better, just write a good game, classic D&D is not it." That may be MY opinion on the topic, and I haven't played AD&D since the mid 90's and barely even 3.x or 5e since then. So, that was me voting on that subject.
But within the bounds of talking ABOUT Skilled Play, I can say that GM skill is heavily required. We have to assume the GM knows how to structure play and deploy his skillset, and how much 'force' to use in order to exactly elicit and reward Skilled Play. We have to accept that THE agenda is to enjoy this type of play. Well, I think we can accept that "people are playing at this table, that must be the case", so the agenda part I basically ignore.
Now, in terms of that trap thread: Clearly we see from it that the content and nature of the fiction is not really going to be perfectly fixed in most/many cases. So, that's certainly where one big part of GM skill has to come in is in terms of writing things up in a way that works to start with, and then running it in a way that leads to player satisfaction that the 'play with skill' agenda was upheld. It is certainly possible, to a degree. I think a big issue is perceived nature of reality.
In that other thread if a player simply discounts the possibility of a particular type of trap from working, he's going to assume that it doesn't work that way, and come to incorrect conclusions about it. Maybe you can say "well, characters make mistakes." OTOH is it skill when you fail because of a misperception? Or is fixing misperceptions a major PART of the skill? I think it is!