K-ON!
only musicians can understand...
I haven't seen K-On, but I'm willing to bet my left nut that Beck is a more accurate representation of what it means to be a musician or band member.
In terms of arts, yes it will hold anime back. In terms of money, they're doing just fine.
And horror isn't always better. Cowboy Bebop, Akumetsu, and Mirai Nikki are a few great examples of non-horror, mature anime.
Are they doing fine in terms of money? I mean how many people here buy anime or at least legally stream it (I'll use crunchyroll if they have what I want to watch, but thats about as much support you'll get out of my broke ass). I understand why companies won't try and expand the target audience, its way to big of a risk, and even if it works they probably won't make any money off it for years. But its still a shame that there is a whole untapped demographic of people who probably would enjoy anime, given it had a decent story and easily view-able (anime movies in western theaters).
Mature doesn't have to be horror, but horror has to be mature. So yeah, I'd agree. But I'd argue about Mirai Nikki being mature.