Agreed - and if anyone is interested in this specific sort of work ("meta-textual" analysis of things like marginalia and the material characteristics of a piece of writing) there is a wonderful resource in Rare Book School at the University of Virginia: https://rarebookschool.org. They offer summer classes and a fellowship program, and it isn't just about old books - when I was there I met people working on digital texts, and even things like the preservation and archiving of VHS tapes and other old analog formats.

Nick Wilding's discovery of a forged Galileo manuscript is another fun example of this type of research: https://www.newyorker.com/magazine/2013/12/16/a-very-rare-bo...