[imtyler]

When it comes to DRM and content hosting, the recent closure of the Microsoft ebook store comes to mind.

If a marketplace is underutilized it risks becoming obsolete. And, unfortunately, sometimes that means loosing access to content.

There are additional considerations, of course. Steam is also a social network of sorts, so fracturing gaming communities is also of concern. But it could also just be that gamers are accustomed to Steam; they like it. And they don't like platforms that don't play well with it.