I'd say they are not political, they are practical. The technical discussion is entirely moot until the editor problem is solved.

Try as they might, and there's a big pot of gold waiting for the first to succeed, no one has been able to develop an HTML editor that normal people can use. Certainly not one with the sophistication to enable them to use the breadth of markup required to even edit the poor meagre subset of syntactical information (not even chapters) incorporated into the elegant products coming from DP.

Microsoft has failed. Adobe has failed (and they have the only product that has real traction for highly technical users.) Google keeps trying with Google Docs, but that's clearly unsatisfactory.

What is technically possible with HTML, X or otherwise, makes no difference at all unless there's an editor supporting it that is approximately as easy to use as what people write their emails with, and captures syntactic artifacts.

The light-weight markup languages are all I've ever seen that try to address this most fundamental requirement. Everything else seems to grind to a halt in the great wysiwyg swamp - an impedance mismatch if there ever was one.

Email hosts and blog engines are the word's two anvils for testing the reality of text editor usability. Anthologize is one attempt to take aim at ebooks from this direction. At least a couple of the  POD/ebook-self-publishing outfits are asking people to submit using blog engines (including B&N.) I can't think of anyone who appears willing, much less eager, to accept HTML text.
 
The format it eventually gets stored in inevitably will the be format it gets submitted in. Any other assumption just adds overhead and loses textual integrity. You can only take out what's put in.