That specific outlier aside; I get the impression that cartoons in Europe and the US picked up quite a bit of slack in the adult demographic with shows like Archer and Rick & Morty in the past decade, building on what Adult Swim prepared in the US. In Japan this niche was already much more explored, although it is not a pass-time most adults flaunt. While I never got the impression that adult viewers of anime were anything more than a (sizeable) minority, they are certainly a target demographic, and manga (comics) even more so. One example that always stuck out to me was former prime minister Asō Tarō who openly admitted to being quite well-read in manga.