Whether or not EPUB is still being developed has absolutely no bearing on the topic at hand. With spec or without, proprietary nonsense (and the downright ignoring of spec) has always meant that book designers must jump through hoops to make things work on multiple platforms. That won't change now that the EPUB specification is considered "nearly complete". DRM also has no bearing on the fact that a scattershot approach to the wide publication of similarly rendering content has always been--and will always be--necessary.
EPUB specifications were largely ignored by EPUB vendors and rendering devices/applications (even open ones) when the IDPF still existed as an independent organization, and they will continue to be largely ignored after. Their continued existence was never going to usher in any golden age of ebook publishing prosperity (nor simplicity).
|