[murraypaul]

Design by committee just doesn't work.
By that time it does arrive, Amazon and Apple's (and probably by that point Kobo's new one, and B&N's fork...) formats will have been out and in use for years, and if a new 'standard' is ever delivered, it will be totally irrelevant.

And for the people asking why Amazon, Apple, ... invent their own formats rather than using the 'standard', this is a big reason. With your own format you can decide exactly what you think is worth supporting and what isn't, how you want to go about supporting it, and you can control both the software generating the books and the software reading the books, so know exactly how things will be displayed.
And you can do it all at your own pace, and get to market quickly.