Is the fact that wide audiences don't want to see child protagonists grow up why many comic strip characters never age?
Maybe. Another reason: David Craig Simpson is a talentless hack and can go snort on a wall of dicks while climbing it so that after he's done snorting it he falls down and is all ":(".
Although it didn't seem like Western RPGs (the old D&D ones or games like Bard's Tale or Wasteland did this - it seems to be primarily a Japanese thing)
You can make characters as young as like, 15 or 16 in Wasteland, and even younger in Wizardry. I'm thinking 9 might be the minimum age, there?
Basically, though, let's compare this to Disney movies. In the 1940s you had a young bambi, who loses his mother, grows up, has babies, and then the forest burns down in a scene of apocalyptic destruction which is a bit unnerving given that the bombing of Hiroshima would only happen a few years later. That's an entirely different kind of child protagonist than in... I don't know. A lot of more recent Disney movies.
I'm not really sure what the hell I'm saying so I guess you could say that the point of a child protagonist is to have them learn something about adult life, leave their childhood behind and move on, or to give a more innocent perspective of a very non-innocent event. And these traits are generally not seen in children's books/movies/whatever to day, and I think it applies to RPGs, too, except now instead of having really stupid kids not doing jack, there are really boring adult characters that don't act like adults and aren't really different from one-dimensional child protagonists. I mean it's all
<Kid> TEEHEE I AM INNOCENT AND CUTE TEEHEE.
<Adult> i fucking hate everything BOOZE PLZ.
I'm not saying this is a universal trend and I don't even know what I AM saying but...
I thought Gabo was a really cool child protagonist. You didn't really see it unless you constantly used the party talk feature, but he was a really good mix of innocence and honest confusion at some of the darker turns in that game.
Ness wouldn't have worked as an adult, either.
I think there's this problem as a whole where a lot of RPG writers have trouble portraying well rounded characters, despite the age. Like, Yangus? He's pretty normal and as a result pretty believable. Whereas Basch is just like, christ dude what the hell is wrong with you, nobody acts like that*? And I think I'd rather have a near-silent lead, like Randi from SoM, than something completely botched.
Maybe that's what silent mains are good for. Younger characters that are just silently taking everything in and seeing how the world works. I do know that SoM wouldn't have worked if Randi was more talkative (I'm pretty sure he wasn't silent, though. Confirmation?).
Spark from Ultima 7, by the way, is totally awesome as a child protagonist. Like, he's 12 or 15 or something. And Ultima 7, being a PC game from the 90s, has a brothel. And you can drag Spark in there with you and it's pretty much the funniest goddamn thing ever. He doesn't act like a REALISTIC early teenager, but he acts like one that makes sense, in the context of the game.
* Vaan actually almost worked, like, in a few scenes where he's talking about his dead brother, but the effect is a bit wrong when you realize he's 17 and not actually a lot younger than that.