[Thrymr]

I'm not an expert, either, and I don't know of much precedent for interviews like this with an individual author being publicly released (say, on the web, rather than in a university archive), but private archival materials are used by historians and biographers all the time. I don't know whether Isaacson or his publisher own the rights, but I'm sure others will ask for access in the future.

I'm not sure about characterizing a biography as a "commercial product"; although although it is the source of the author's livelihood, and the publisher is a for-profit entity, it is a complex entity as a product. The author depends in this livelihood in having access to materials from others, it is not unreasonable to think he may reciprocate in some circumstances. In any case, in future years (after the initial sales peak of the bio), releasing the source documents may even cause a revival of interest that helps residual sales.