I can think of plenty of people who woulds be more likely to buy Kamichu! or Princess Tutu than anything "splattered in blood with flesh everywhere" – primarily, the large majority people with two X chromosomes, or, alternatively, a Kinsey scale higher than 3. Possibly also anyone younger than 12 or 15 (as much else wouldn't be legal for them to purchase). My mother, for example, loves Haibane-Renmei, but dislikes anything else on region 2 other than a few of the Ghibli films.
Now let's test your theory. Let's look at the anime DVD charts on Amazon.co.uk. And look what's at the top – Tales from Earthsea and My Neighbour Totoro. Yes, there's Ghost in the Shell right beneath them, but these top two, and Totoro in particular, hardly fit your description.
The failure of Geneon, from my point of view, lies in the inability of anime specialists to get their products bought by anyone other than teenage boys. This is a deep-rooted problem which goes back much further than simply how they market things, though it has been exasperated by this. Essentially, it lies in the public's perception of "anime" as a genre (rather than as a shorthand word for the animated output of one particular country) – this myth was greatly encouraged by distributors during the '90s, as it encouraged people who liked one title in particular to try out other anime which they had the licence to. This kept everything going along nicely enough for a decade or so, but are two great negative side-effects to this marketing trick.
The first, and most obvious, is that because anime is perceived as a genre, if someone sees an anime and does not like it then they presume that all other anime is similar to that, and so avoid it as a whole for the rest of their life (unless someone intervenes to change their mind). The second is just as important, but it is only very recently that it has become all too apparent – this is that it has limited the type of anime which can be successfully released in the west. Because people think of anime as a genre, or, more commonly among fans, being divided into a few stereotypical formats, when they see something which defies this categorisation, they dismiss it as being not really anime. And so, because these fans are the only people who know about it, and the distributors are unable to reach the majority of people who would appreciate it, series like Haibane-Renmei fail to get the sales which they deserve.