We'll have to agree to disagree then.
I've never been fully onboard with the "KF8 is just a compiled ePub" oversimplification. In a very loose, layman's overview ... perhaps. But that's beside the point. The truth is: the IDPF could disband tomorrow and Amazon would just take on the responsibility of publishing their own kindlebook source code specifications. After all ... a KF8 ebook can still be made from nothing other than a single html file. That's why the "executable written in 'C' has no stake in the 'C' standard" allegory isn't all that apt. You don't
need an epub to create a KF8. The InDesign plugin renders InDesign documents into kindlebook source code.
Sure, they have an
interest in ePub specifications, but they don't really care if there's ever any overwhelming compliance in how all those epub specs are
interpreted by developers creating epub rendering engines. Why would they?
So yes ... they have a stake in the specs themselves I suppose. Just no stake (or interest) in how those specs are interpreted (complied with). Their ebooks will never be read by all those devices/apps that can't agree on how the epub specs should be interpreted.