Despite all our advances, we lack an editable, local, multimedia, platform (and form-factor) independent, self-contained file - essentially a word-processing file for the 21st century (and I mean it's almost a quarter-century overdue). epub has that potential as a format, and being based on web standards it has capability, a universe of supporting tools and technology, and easy adoption to different applications.

But I haven't heard anyone else express that particular interest, and as of a few years ago epub doesn't allow annotations and is not stable (i.e., I don't know that today's epub file will be readable in 20 or 50 years) - two essential requirements for a serious local content, imho.

And even if it meets those specifications, we need epub editors that are the equivalent of word processsors for non-technical users.