Amen to that, in the general!
In the specific, as an animation junkie and proponent of "it's a medium, not a genre"... that bias that sees non-hyperreal animated movies as "kids' stuff" and turns adults away is unfortunately a big factor. Unless you're a proven big name like Pixar or Dreamworks - and often even then! - you've got an uphill struggle if you're putting out an all-ages animated feature. There are always some standouts - Spider-Verse, Arcane etc - but the bias is sadly pretty pervasive.
But we also can't attribute everything to that - after all, the film currently kicking TF1's ass is another, much more polished-looking all-ages animated feature from Dreamworks. When I said a whole movie that looked like the BB movie's Cybertron scene would be targeted at older fans, I wasn't (only) talking about the "realistic" rendering but about the whole aesthetic: heroic-proportioned bots leaping around the place, blasting and punching each other to shreds over a constant backdrop of explosions. Though I haven't seen it yet, my understanding from the discussions is that that aesthetic would have been badly mismatched with TF1's overall tone and story style. (The other thing to note is that it would have been
much more expensive, and on current performance would likely have turned TF1 from modestly profitable to a financial flop.)
I hear that the full movie has some gorgeous visuals, particularly vistas and individual scenes, but that initial trailer (the only thing I've really seen besides the Kayou cards, by intent, which puts me in a similar position to much of the prospective audience) looked fairly mid-tier on the level of both character design and animation - more like a game cutscene than a full movie in places. The character designs are serviceable but not really much more than that, pretty generic and interchangeable, and the animation was weirdly stiff at times (B-127 turning and running was a standout in my memory, along with that shot of Dread/Darkwing looking like a cheap, cobbled-together game extra). For contrast, TF Prime, while much less advanced in the rendering and 14 years older, managed some excellent character animation on a much lower budget!
If there's one thing I can assume for The Wild Robot, based on Dreamworks' past record, it's that it will be polished to a high sheen, with characters carefully tuned for audience appeal. That polish & appeal in the design is what I felt was lacking in TF1's marketing presentation, and the cut of the initial trailer ("Badassitron"

) really wouldn't help raise it to must-see rather than meh if I wasn't already invested as a TF and animation fan. Which is a crying shame, because from everything I've heard the rest of the movie is excellent.
--EDIT--
I'm probably coming off as more negative than I mean to. I'm tired. Really just rambling on designing for appeal and the need to make the story, presentation and marketing all line up the same direction for the target demo.