Respectfully, I think this is incorrect. The first statement that I take issue with - that "more established members say" is what I believe logicians call an appeal to false authority. Illogic like this is what makes the myth exist. Being a "more established" member of this board is meaningless without some bona fides. Find me a member of this board that went to Cornell in 1958 and who was into fashion then, as he is now, and I'll listen to him about the way things used to be and ought to be now. By contrast, show me a 20-something from the midwest who went to a state school who has read a bunch of posts on this website and has access to his dad's credit card to buy at Brooks Brothers and I'm not going to give deference to his statements about the way things "used to be."
I should have qualified my "more established" designation. But first, let me go back to what I see as the definition of trad, from my time reading this forum. Some trace the usage of "trad" back only to 2004, with the creation of this forum on Ask Andy, while others refer to Alan Flusser using the term (though I'm not sure exactly where) as well as its use in Japan, apparently as a reference to a certain traditionally American style. Whenever the term was created, it seems the meaning is essentially the same: something of a shorthand for the traditional natural shoulder Ivy League look, though more narrowly defined.
"Trad" is not the same as "classic American style," though it fits somewhere on the continuum. "Classic American style" certainly allows for darted jackets, uncuffed pleated trousers, etc. A simple charcoal business suit with a darted jacket and pleated trousers is no less classic American than its cousin with a 3/2 sack jacket and flat-front trousers. But, the latter is defined as "trad" while the former is not. To be honest I'm not certain why, but that's how it's defined, around here at least. And I think that's the point of this forum: to allow a space for members to discuss the ins and outs of a relatively small niche style.
So, back to my appeal to the "more established members." By that I didn't mean those with the most posts, or those who are oldest, but simply those who know the trad style. They don't have to know all the ins and outs of what people wore in the 50's, because that's not what trad is. It is, again, based in part on what was worn in the 50's (and while you almost certainly could connect anything available today to that decade, it was
the heyday of the Ivy League look in America and so is especially relevant here), but you can look all around the internet and find photographs of men in sack jackets and penny loafers and madras shorts and so on from those years, so there is, to my mind, no need to have lived it to know how the style should be now.
Anyway, I think we're both approaching this from two different points, so it seems we're just going around in circles. My basic point, I think, though perhaps I have misplaced it somewhere along the line, is this: "trad" is a sort of composite style that has cherrypicked some stuff from the 50's, some from the 60's, probably some from the late 40's, some from the 80's, and will probably continue to do so as 'new' things arise. Or maybe not. Maybe "trad" is so narrowly defined that very little gets in, while considerably much is left in the close-but-no-cigar category. Whatever the case, I'm tired of thinking about it for the moment.
At the end of the day, I'd say that I favor a classic American style. Some of it's trad, some of it isn't. (I don't mind darts, for example, so long as a jacket has a natural shoulder.) Or maybe the definition of "trad" does allow for the darted natural shoulder jacket and my understanding of "trad" is wrong. Either way, I wear what I like, and it works.