Yeah I guess you're right, hadn't really thought of it like that.Whereas in regards to the franchise and not the show, TNG just is 'Star Trek' really.
Let me guess. You didn't grow up in the sixties or seventies, right?
Like I said, this is a generational thing. Nobody my age is likely to concede that "TNG" trumps everything else.
Don't get me wrong. I watched all the latter-day shows religiously, too, but TOS is Star Trek to me. Just like TNG is to you.
I got into Trek about 1993-94ish, aged 9-10.
I think I just said that as a provider for my love of Star Trek after that was collecting the Star Trek Fact Files, from early 1997 to late 2002. And because the one image they used on all the folders was a shot of the Enterprise-D. Not the 1701, not the A, not DS9, not Voyager, but the D.
And even now on the recent Star Trek: Stellar Cartography book, they could've picked any ship to represent the franchise, and they chose the Enterprise-D.
So that's kinda why I think that.
(Interesting that on Star Trek: Star Charts they used the NX-01, but as it was released in 2002 I think that was more a marketing decision as it was the "current" ship.)
The Fact Files were based on the Star Trek Chronology and Encyclopedia, both the work of TNG staffers (Mike Okuda) and released during TNG's peak. It was their version of the universe, so to speak, somewhat different to the TOS and movie-era stuff previously published. Having a TOS ship on the front of volumes of TNG technobabble would have been weird.