Studios making games that can be profitable with 100k sales are the ones staying open. There are a few big-shot publishers selling millions of games, but that's not a sustainable business model for most developers. This is why indie studios are doing so well -- they keep their overhead down.
If you take a look at Epic Mickey 2... they probably could have made the same game for Wii only with very little budget, reusing a lot of assets from the first game. But instead they ported it to three other consoles, all of them HD consoles at that, and PC. Maybe they still would have lost money, maybe they still would have closed. But I'd wager that whatever they spent on that Wii U port, it wasn't worth it, not for 80k sales. PS3 with 210k isn't much better, nor 360 with 260k.
