That seems to be why the most popular advanced topics are conference talks instead of books. Still takes prep and you lose the quality of a tome, but an hour long talk (possibly with decently annotated slides for later viewings) is probably better worth for the speakers and audiences alike. conference foots the bill with the costs gathered from participants, participants get a variety of talks (so they aren't paying for one tome but maybe a dozen nuggets to serve as jumping off points. Which may be all an advanced participant needs), and the industry gets advertising/potential recruiting from the staff they dispatch.

Of course, I'm sure I don't need to explain the downsides of a talk, Especially one presented by very knowledgable people but not ones who are necessarily expert speakers. But at the same time, that lack of polish may be a light in the darkness that is false platitudes in every other ad.