Old-skool fan checking in here.
I've been an anime fan since I was twelve and I'm now twentysomething... ish. During that time I have seen the market absolutely
explode (and yet I still can't get
Weiss Kreuz on DVD because it never got a UK license. Go figure that) to the point that I can now walk into pretty much any major bookstore and grab translated manga from a 'manga' section. Back when I first got into anime and manga, you bought an overpriced and badly dubbed copy of
Akira in which Kaneda was voiced by Leonardo from
Teenage Mutant Ninja Turtles, or you didn't buy anything at all. The 'manga' section in most bookstores was half a shelf next to a load of DC and Marvel TPBs, and it contained perhaps the same two or three overpriced volumes of
Ranma 1/2 and
Ironfist Chimni. If you wanted anything more adventurous, you had to get it imported and get the translations off the Net. Much of my manga collection is in Japanese, not because I can read it, but because when I was able to buy lots of it, there was no other way I was going to get to read the things I wanted to. That's now changed, and I'm glad of it.
It's not really surprising that a couple of companies are going under, though - the economy's in the crapper, the market is oversaturated, and there are too many small companies anyway. Manga was the Next Big Thing for a while back there and a lot of people got into it without really knowing what they were doing or having any real long-term plans simply to make a quick buck, and while a lot of good stuff got released, a fair amount of second-rate titles were bought and localized simply because they were manga and hey, kids love manga! Now the novelty's wearing off and people aren't as interested in buying any old manga or anime regardless of quality just because it's from Japan. Consequently sales will fall off and the smaller companies will go under or get bought out, and you'll be left with a handful of large companies that deal with damn near everything. This happens with every next big thing: lots of companies try their hands at it and a handful will thrive while the rest go under or get bought out by the big boys. The same thing happened with cars, with dotcom companies and with Western comics to name but three.
Geneon didn't really have a very good business model - releasing niche shows and charging a fortune for the box sets isn't really a sustainable way to run a company. They had no big-name shows and simply couldn't keep up with the rest of the pack, so they went under. This is probably going to happen a lot. It's very unlikely manga and anime will stop being released altogether, but it seems likely things will slow down somewhat. The market's glutted as it is.