Seems like a slightly biased article to me. The author took several opportunities to demonize one company for using DRM (bad, bad), yet nothing was mentioned about the vast majority of epubs that are
also plagued with DRM. But otherwise, I agree... I'd love to see multiple formats offered by more ebook sellers--but I'm not at all interested in forcing anyone to sell anything but their own chosen format if that's the way they want to do business. Let Darwin sort it all out.
The problem has never been "too many formats"... the problem is DRM. Without it, nobody would be screaming for "one format to rule them all."