Story-wise vast majority of RPGs have always been decidedly young adult material. In book terms that's Eragon or Harry Potter territory for you. Lowest common denominator 2OP to resist.
Target demographic isn't an issue. Eragon had the same targeted demographic and almost the same story as A New Hope, but bi one un hua right mind would put them into the same category of quality. Same thing about HP, as I quite liked them (first 4 of them, as I hardly remember the rest), and if games on average would have been at least half as competently written as them, there wouldn't be a problem.
If you want make a point about demographic, much better to say that the younger targeted demographic is the more talentless mediocrities wrote for them, as it easier to make money spending much less effort. But not always, as there aren't many masterpieces for middle-aged housewives for example.