The game is more than 20 years old at this point. It can legally by alcohol in the US. Anyone who played BG3 when they were young is mature enough to deal with an M rated game, and people who aren't old enough probably aren't going back and playing the originals, as they have mechanics that don't jive with modern sensibilities in gameplay.
I am thinking about your argument, but that’s what Dragon Ages, or Pillars of Eternity attempted - more mature universes, for more mature audience, new IPs. In case of BG3, I just don’t see what the benefit is of limiting its audience. From the cynical point of view, what you say makes sense - older audience is unlikely to mind 18+ and all the cursing, boobs and poop could attract teenagers to what isn’t exactly “cool†genre to play. Still, the end result I suspect will be a game much less timeless as the originals. The mix of characters like Minsc and Boo, talking squirrels, looney toones push and R rated content will be very grotesque.
Edit. Meh, to end with a I would like to share a video essay, from which I stile James Gunn’s quote couple pages earlier. It revolves around R rated superhero films, which I think is the best parallel to what is happening to BG.
