But how is Amazon "disintermediating" anything? It's simply taking the place of a previous intermediary (bookshops). The next step will be that authors will sell to readers directly; that will disintermediate both publishers and Amazon, and there's no reason it should not happen.
Au contraire: the reason it won't happen is that most folks are not tech-savvy geeks. Most writers want to write, not deal with the minutiae of self-publishing (which is not the same thing at all), and most readers who buy ebooks aren't savvy enough about downloading files and shoving them onto a peripheral device. Oh, and reading books is already a marginal activity: anything that reduces the size of the market by e…
When it follows the rules, disruption starts at the low end, competing with non consumption and its near margin. Lots of books can't be viably published via the old system but might still be viable fo self publishing. For example, a book that can expect 2000 sales.
The question is not necessarily will the established authors & publishers prefer "to write, not deal with the minutiae of self-publishing." The question is will future authors prefer to try and find someone willing to publish their books or will they just self publish? I think a lot of them will self publish.
The second reason is cost. The traditional publishing process is expensive. It's an all exclusive package that includes financing, editing, promoting and all sorts of other stuff that authors probably want to avoid but it costs. Authors earn a small percentage of the price of a book. From what I understand, it can be between 1% & 25%. That is a lot of room for improvement.