I think the down votes are because the post is ultimately about the reliance on online libraries being flawed, which steam certainly is. Honestly, it often feels like steam will be around until the heat death of the universe, but alas I always figure I'm good though at piracy that all my purchases are essentially a donation, anyway.
That said, I think I heard that they have a policy that if it were to come to that, any files made local on your machine are yours and can still play them. Might be tricky if it's drm and they go poof, though.