Actually, Japan is grappling with a stagnating population issue at present where the birthrate has declined while the average age of its people grows older due to heightened life expectancy. Some consider it a crisis and the implications of it echo throughout modern Japanese philosophy and the media which tackle it. It's all tangled up with other cultural factors like the deterioration of the relationship between men and women, hikikomori, herbivore men, parasite singles, and a pervasive sense of complacency. Parallels with certain modern happenings in the west are noticeable.
But I mention this because the impact of the lack of children being born in Japan is more extravagant than a lot of people realize. Elementary schools are being shut down throughout the nation because there's just not enough local children around to attend them.
So what's ended up happening is that, to survive, manga and anime cater not just to children, but teenagers and adults as well, which is why anime tends to include more mature (though not necessarily more sophisticated) subject matter. Furthermore, otaku are an extremely lucrative demographic to pander to, so they do in various ways. As expected of passionate and dedicated nerds, however, they're also incredibly temperamental, so misjudging their values when you're writing a story to appeal to them can spell disaster, leading to very minimal risk taking.
How the light novel industry (and, by extension, the web novel industry, since ASCII picks up successful works from the Japanese WN hub Syosetu) has affected anime and otaku culture is pertinent as well, given how many anime are simply single season adaptations of LNs, essentially advertisements to buy the LNs the same way GI Joes were commercials for toys. Most LNs are published through ASCII Media Works, a subsidiary of the cutthroat Kadokawa Co, which, again, will dumb down works to make safe decisions.