I just miss manuals, dead tree or otherwise. Where’s the manual for my iPhone? It’s just a vast unordered, sprawling, inconsistent, incomplete subsection of apple.com.
What I miss are schematics and parts lists. Of course, that would be virtually impossible with today's electronics, short of a bunch of PDF documents or something. Even then, they would almost be worthless.
But...back in the 1980s, just about any electronic device you bought (especially if you bought it from Radio Shack), the manual would have a schematic in the back, plus a list of parts (and in the case of RS - the parts list would usually have part numbers you could pick up off-the-shelf at the store!).
There's too many black-box chips on a typical product to make any sort of schematic meaningful.
There used to be full wiring diagrams for cars in manuals, but imagine that now where your car has 200 separate computerized systems, each with their own intricate circuits.