Yeah, I'm not sure about that? I mean, yes, that's exactly what it means, it'd be dumb to argue that lol but that's not how people generally see that nowadays, is what I'm trying to say. "For all ages" kinda turned into "safe enough for anyone to watch" which is not the same as being for all ages.
There's a few movies and shows from my childhood that I remember striking a chord in me then, that I can deeply connect with now in such a way I couldn't before. And then there's a few that were fun to watch.. that just not only offer nothing to me as an adult, but they're not fun anymore either. Though that might just be me having developed different tastes as I got older. In any case, both methods of handling media aimed at kids have always been there, I feel.
I fondly look back on the Disney movie, Treasure Planet for being a case of a mature children's movie. If there's any animated film aimed at kids that I've watched more as an adult.. it's that one. The technical aspect always amazed me in how the traditional 2D animation and 3D CGI stuff can work so well together. The story of how long it took John Musker and Ron Clements to finally get to make the movie after it was originally pitched in 1985. The Jim and Silver montage breaks my heart even more once it gets to Jim's childhood memory of his father leaving the family, especially knowing what comes after said montage. It was cool to watch as a little boy, but it's much better to watch now as I can appreciate and understand so much more of it. (except for Ben, never liked him much even as a kid lol) So yeah, it might be a cartoon movie, but it's got a lot more heart than a lot of stuff in live-action nowadays. Media made for children should never be dismissed~